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Differential conductance of submicron HEMT is analytically investigated as a function of drain bias for different structural parameters and parasitic effects. Simulation is carried out for two different substrate based devices, Si and... more
Differential conductance of submicron HEMT is analytically investigated as a function of drain bias for different structural parameters and parasitic effects. Simulation is carried out for two different substrate based devices, Si and sapphire, and comparative study is carried out for those structural parameters at which VGS provides maximum transconductance. Poisson's equation and carrier density equations are simultaneously solved to get drain current variations and parasitic effects are invoked through boundary conditions for realistic results. Result speaks that effect of threshold voltage is negligible on sapphire based device over a wider range of horizontal bias. Nanometric channel length provides almost constant conductance profile with insignificant magnitude.
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Based on the climatic conditions like temperature and humidity of the soil, a novel robot is designed which can assist farmers for judging the requirement of water and fertilizer. An efficient algorithm is made for this purpose, which... more
Based on the climatic conditions like temperature and humidity of the soil, a novel robot is designed which can assist farmers for judging the requirement of water and fertilizer. An efficient algorithm is made for this purpose, which sets the threshold level for decision making purpose for different requisites; and also plot the real-time data based on the pre-defined optimum level. Owing to its movement capability, it is able to provide the water and fertilizer at the specific places till the reference level is reached, and then moves thereafter. It also uses remote sensing for determining insect stress and applies insecticides as per requirement. In our agricultural-dominated country, the present solution is a much-needed solution for harvesting problems.
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Lowest two quantum states of a double-well-triple-barrier structure are numerically analyzed for Pöschl-Teller potential profile. Kane-type band nonparabolicity of first order is considered for rational replication purpose, and effective... more
Lowest two quantum states of a double-well-triple-barrier structure are numerically analyzed for Pöschl-Teller potential profile. Kane-type band nonparabolicity of first order is considered for rational replication purpose, and effective mass mismatch between well and barrier layers are included in the computation following the BenDaniel Duke boundary conditions. Transmission coefficient is plotted as a function of input energy flux, and peaks are identified for eigenstate determination in presence and absence of external electric field. Results are compared with that obtained for ideal rectangular geometry, and better quasi-peak characteristics speaks in favor of the proposed structure for photodetector application, where tailoring of subband energy can be achieved by means of structural parameter variations.
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Ripple factor of ternary photonic bandpass filter is analytically computed around 1.55 μm under normal incidence of electromagnetic wave. Parallel nanorod is considered as the metamaterial for the simulation purpose with air gap, and... more
Ripple factor of ternary photonic bandpass filter is analytically computed around 1.55 μm under normal incidence of electromagnetic wave. Parallel nanorod is considered as the metamaterial for the simulation purpose with air gap, and transfer matrix technique is adopted for the investigation. Improved noise rejection characteristics are obtained compared to the published results for positive index materials. Different structural parameters are varied to observe the bandwidth as well as noise variation for optimized performance. The structure is taken as defected one, where the density of point defect is within the limit of fabrication, so that the simulated findings can be taken as realistic.
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A novel package is proposed using JAVA-GUI platform for analyzing filter performance with one-dimensional photonic crystal. With this package, user can provide the required structural parameters (within fabrication limit) for maximum 11... more
A novel package is proposed using JAVA-GUI platform for analyzing filter performance with one-dimensional photonic crystal. With this package, user can provide the required structural parameters (within fabrication limit) for maximum 11 layers 1D structure; and bandpass characteristics can be obtained for both the polarized input conditions. Results are provided for SiO2-air composition, and can be obtained for other material systems with positive refractive indices. Package is useful prior to fabrication for optimizing filter performance.
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Lower return loss and isolation loss of 1-bit RF MEMS switch is analytically investigated for different dielectric materials over the L band to K band. Both unactuated as well as actuated conditions are taken care for simulation purpose,... more
Lower return loss and isolation loss of 1-bit RF MEMS switch is analytically investigated for different dielectric materials over the L band to K band. Both unactuated as well as actuated conditions are taken care for simulation purpose, where overlap area is kept constant. Simulated findings reveal that both the losses are significantly reduced for lower dielectric constant material (SiO2) compared to higher permittivity (Si3N4) upto 30% which is an indirect estimation for measuring upstate and down-state capacitances. Results are also compared with existing data from published literature which speaks in favor of the present work for phase-shifter design.
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In this paper, an efficient synthesis technique for high-speed multivalued ALU for \((2^{p} \pm q)\) radix system is proposed with reduced complexity. Addition, subtraction, increment/decrement and basic logical operations are implemented... more
In this paper, an efficient synthesis technique for high-speed multivalued ALU for \((2^{p} \pm q)\) radix system is proposed with reduced complexity. Addition, subtraction, increment/decrement and basic logical operations are implemented just by rotation of the matrix or shifting of a few elements, and thus minimum number of computational steps is involved; which saves CPU time usage. Matrix representation for all the operations is provided in a tabular manner with pseudocode for the proposed \((2^{p} \pm q)\) radix system in order to understand the detailed procedure of operations. All the pseudocodes have been verified using Xilinx ISE 14.1 simulator using Vertex-7 XC7VX330t device. Lower computation time and complexity make the ALU efficient than those already proposed in the available literature.
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Quantum-confined states of electrons inside quantum ring-like structure have been analytically investigated subjected to crossed electromagnetic field in order to study the effect of field quantization. Schrodinger equation without... more
Quantum-confined states of electrons inside quantum ring-like structure have been analytically investigated subjected to crossed electromagnetic field in order to study the effect of field quantization. Schrodinger equation without considering time-dependency factor is solved with boundary conditions based on the cylindrical geometry of the structure, and lowest two orders Bessel functions are considered for the evaluation of electron energy states. Result reveals that while perpendicular electric field lowers the energy subbands, parallel magnetic field makes the opposite effect; thus creating an interesting trade-off situation. The result is weighted against with that acquired independently in absence of electric field and magnetic field respectively for identical dimensions. The present work reflects this energy optimization by simultaneous tailoring of both the fields in order to obtain absorption and emission spectra.
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Theoretical computation of eigenenergy and transmission coefficient for symmetric quantum double barrier structure considering GaAs/Al xGa 1-xAs material composition has been carried out using transfer matrix method to study the resonant... more
Theoretical computation of eigenenergy and transmission coefficient for symmetric quantum double barrier structure considering GaAs/Al xGa 1-xAs material composition has been carried out using transfer matrix method to study the resonant tunneling phenomenon under 1-D confinement which is a quantum-coherent mechanism, and also to study about the existence of quasi-bound states when the device is subjected to electric field. Device is made dimensionally asymmetric to observe the variation of tunneling probability in presence and absence of electric field to compute probability of resonant tunneling at specific energy values less than barrier potential.. Effective mass mismatch at junctions are considered throughout the analysis by varying the mole fraction of Al to estimate near accurate values of eigenenrgies and also of the transmission probabilities. Application of negative bias makes the possibility of quasi- bound states near zero energy.
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Transconductance of high electron mobility transistor is analytically computed by simultaneously solving Poisson's equation and carrier density equations subject to appropriate boundary conditions in nanometric dimension. Static and... more
Transconductance of high electron mobility transistor is analytically computed by simultaneously solving Poisson's equation and carrier density equations subject to appropriate boundary conditions in nanometric dimension. Static and transfer characteristics are obtained for low biasing ranges from which device transconductance is computed. External biases, threshold voltage of the device and source and drain resistances are considered to analyze the effect on device transconductance. Peaks of the transconductance plots are obtained at lower V GS, and decreasing nature is seen at with increase of vertical bias. Results are suitable for using the device as amplifier in nanoelectronic circuit.
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The subthreshold slope of a submicron high-electron-mobility transistor (HEMT) is analytically computed as a function of vertical electric field for various parasitic effects and structural parameters. The simultaneous solution of... more
The subthreshold slope of a submicron high-electron-mobility transistor (HEMT) is analytically computed as a function of vertical electric field for various parasitic effects and structural parameters. The simultaneous solution of Poisson’s equation and the carrier density equation provides drain current from which subthreshold slope is calculated subject to appropriate boundary conditions. Simulation is carried out at optimised channel length and applied bias for which maximum transconductance and higher differential conductance are already reported. Results show that for a particular range of gate-to-source bias, V GS, simulated findings match very closely to the ideal value of 60 mV/decade. The role of an aluminium nitride (AlN) buffer layer in tailoring the subthreshold slope magnitude is critical and the effect of submicron channel length, which is otherwise absent in conventional HEMTs, is explored. A combination of both the electric fields in realistic situations is investiga...
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Optical bandwidth of bandpass filter with metamaterial based defected one-dimensional photonic crystal is analytically computed. Two different metamaterial namely parallel nanorod and nano-fishnet with elliptical void are considered for... more
Optical bandwidth of bandpass filter with metamaterial based defected one-dimensional photonic crystal is analytically computed. Two different metamaterial namely parallel nanorod and nano-fishnet with elliptical void are considered for the design of bandpass filter, and both normal and oblique incidences (with all types of polarization) are considered for analyzing performance. Defect density is considered within practical limit for making the simulated output of practical importance. Structural parameters are tuned within fabrication limit, and angle of incidence are also tuned within feasible limit for which bandwidth is determined. Theoretical findings have practical importance as filter with sub-micron bandwidth can be utilized in all-optical integrated circuit.Optical bandwidth of bandpass filter with metamaterial based defected one-dimensional photonic crystal is analytically computed. Two different metamaterial namely parallel nanorod and nano-fishnet with elliptical void are considered for the design of bandpass filter, and both normal and oblique incidences (with all types of polarization) are considered for analyzing performance. Defect density is considered within practical limit for making the simulated output of practical importance. Structural parameters are tuned within fabrication limit, and angle of incidence are also tuned within feasible limit for which bandwidth is determined. Theoretical findings have practical importance as filter with sub-micron bandwidth can be utilized in all-optical integrated circuit.
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Filters in all-optical circuit have the potential advantage over that of optoelectronic circuits because of very high SNR, thanks to the reduced scattering between photons instead of electron-electron collisions. This property makes the... more
Filters in all-optical circuit have the potential advantage over that of optoelectronic circuits because of very high SNR, thanks to the reduced scattering between photons instead of electron-electron collisions. This property makes the PhC based filters as the blue-eyed candidate for optical signal processing in photonic circuits. Semiconductor heterostructures are in general the constituent element of photonic crystal (PhC) based devices, whose performance is characterized by passband width at the desired frequency of communication spectrum, along with magnitude of ripple in that region of interest. The present paper shows that effect of device temperature has a great deal of influence on the performance parameters of the filter, under different polarized conditions and different magnitudes of structural parameters within physically realizable limit. But modulation of bandwidth is negligibly small as observed from simulated results within the choice of temperature range. Results are critically constructive for inclusion of this filter in optical integrated circuit.
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Insertion loss, isolation factor and return loss of one-bit RF MEMS switch designed at higher microwave frequency ranges is numerically measured for computation of up-state and down-state capacitance. SiO2 is the material considered for... more
Insertion loss, isolation factor and return loss of one-bit RF MEMS switch designed at higher microwave frequency ranges is numerically measured for computation of up-state and down-state capacitance. SiO2 is the material considered for design purpose and simulation is performed over the entire microwave frequency range in order to investigate the position of maximum loss (peak point). Overlap cross-sectional area is varied over the possible fabrication range, and losses are measured for both actuated as well as unactuated states of the device over the varying overlap region. Both up and down state capacitances are measured which are higher with increase of active area. Return loss of −50 dB is observed for unactuated state whereas it becomes very low (~ −7.5 dB) for actuated device. Also for down state capacitance measurement, isolation increases upto −40 dB. Results are very useful for phase-shifter design at microwave spectrum.
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Subthreshold current for heterostructure pMOSFET is analytically explored as a function of applied bias for Si-SixGe1-x material system in presence of band-to-band tunneling. Threshold voltage of the structure is calculated considering... more
Subthreshold current for heterostructure pMOSFET is analytically explored as a function of applied bias for Si-SixGe1-x material system in presence of band-to-band tunneling. Threshold voltage of the structure is calculated considering body effect for different structural parameters, and mole fraction of Ge is chosen as 0.28 for that operating point where 2DEG is yet to be formed, and thus suitable for estimating subthreshold conduction. Using this optimum structure, BTBT effect is incorporated to measure the drain current for a range of source-to-gate voltage (VSG), and results suits in excellent with available experimental data for very low and higher values of source-to-drain voltage (VSD). Result is also computed in absence of tunneling effect, and drastic variation is observed which speaks in favor of our proposed model of subthreshold conduction. A monotonic decrease of subthreshold slope is observed with increase of VSG, which speaks for the optimum biasing criteria for operation of the device in order to minimize the leakage current. Results are in favor of applying the model for sub-22 nm FinFET or even sub-10 nm TFET devices.
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In this paper, millimeter-wave signals are generated with characteristics of high gain and low noise using optical frequency comb, where generated signals are tunable at a wider range (approx 50 GHz in both the sides) around the central... more
In this paper, millimeter-wave signals are generated with characteristics of high gain and low noise using optical frequency comb, where generated signals are tunable at a wider range (approx 50 GHz in both the sides) around the central frequency 94 GHz. Concept of electrical mixing is incorporated to achieve the tuning of the signals. Result shows that adopted methodology is far superior to conventional optical mixing and stable, high gain and low noise microwave signals are obtained in all the tuned frequencies. Wider tuning range speaks about the supremacy of the proposed scheme both in optical as well as in RF spectrum.
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Threshold voltage (with and without body bias) for heterostructure pMOSFET is analytically explored as a function of applied bias for Si-SixGe1-x material system in presence of band-to-band tunneling. Threshold voltage for given device... more
Threshold voltage (with and without body bias) for heterostructure pMOSFET is analytically explored as a function of applied bias for Si-SixGe1-x material system in presence of band-to-band tunneling. Threshold voltage for given device structure is calculated in the light of body effect for different structural parameters, and mole fraction of Ge is chosen as 0.28 for that operating point where 2DEG is yet to be formed, and thus making it apposite for estimating subthreshold conduction. Using this optimum structure, BTBT effect is incorporated to quantity the variation of threshold voltage over a range of source-to-gate voltages (VSG). The results accord with available experimental data for very low and higher values of source-to-drain voltage (VSD). Result is also computed in absence of tunneling effect, and drastic variation is observed which speaks in favor of our proposed model of subthreshold conduction which can be further extended for modeling of sub-threshold drain current characteristics of HFETs.
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Drain-to-source current of independently-driven double gate (ID-DG) MOSFET is analytically computed following Ortiz-Conde model in sub 100 nm channel length in presence of different high-K dielectrics. Fowler-Nordheim tunneling concept is... more
Drain-to-source current of independently-driven double gate (ID-DG) MOSFET is analytically computed following Ortiz-Conde model in sub 100 nm channel length in presence of different high-K dielectrics. Fowler-Nordheim tunneling concept is invoked due to reduced dielectric thickness; and front gate control is tailored to analyze the effect on current and pinch-off voltage. Excellent agreement is observed with published literatures for high front-gate voltage when device is lightly doped; which speaks in favor of the work within dimensional constraints. Percentage change of current considering body effect is estimated for different gate bias. Result speaks in favor of low power analog applications.
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Fill factor and conversion efficiency of single heterojunction solar cell is analytically computed based on the shallow doping at GaAs quantum well region. Poisson’s equation is solved with suitable boundary condition applied at... more
Fill factor and conversion efficiency of single heterojunction solar cell is analytically computed based on the shallow doping at GaAs quantum well region. Poisson’s equation is solved with suitable boundary condition applied at hetero-interface for both dark and illuminated conditions, corresponding to which open-circuit voltage and short-circuit current are computed. Realistic dependence of minority carrier distribution on material layers and diffusion widths are taken into account for simulation purpose. Result exhibits that variation of acceptor density leads to better outcome in terms of both efficiency and fill factor, which is also critically depends on length of quantum well region. Doping of AlGaAs barrier layer has negligible influence on fill factor and conversion efficiency. Optimized dimension of quantum well layer width is the critical parameter for design of efficient solar cell, as revealed from the analysis.
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Transmissivity of 1D defected photonic crystal is computed using transfer-matrix technique as function of wavelength for TM and TE mode of propagations. Layer dimensions and incidence angle are varied within practical range to study the... more
Transmissivity of 1D defected photonic crystal is computed using transfer-matrix technique as function of wavelength for TM and TE mode of propagations. Layer dimensions and incidence angle are varied within practical range to study the change in wave propagation characteristics computed around 1.55 µm. Normalized defect density is varied within acceptable limit to observe the variation of transmission, which plays key role for application of the structure as band-pass filter. Results revel that defected crystal can be implemented in designing photonic b.p.f with acceptable passband width and confinement at the cut-off frequencies for optical communication.
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Drain current and pinch-off voltage of ultrathin double-gate MOSFET are analytically calculated based on Taur’s model, where the centre potential is derived from Ortiz-Conde formulation. Drain current is computed for different structural... more
Drain current and pinch-off voltage of ultrathin double-gate MOSFET are analytically calculated based on Taur’s model, where the centre potential is derived from Ortiz-Conde formulation. Drain current is computed for different structural parameters in lower nanometric range, and the effect of the high-K dielectric is investigated. Pinch-off voltage shift is therefore derived from the simulated findings and compared with the available findings followed by Ortiz-Conde. The result shows a measurable variation in the parameters, and the root cause is explained from the electrostatic point of view. Findings are important for conductance calculation.
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Spectral response of GaAs solar cell is analytically computed incorporating the existence of quasi-Fermi level generated after photon shower. Analytical computation is carried out for simultaneous solution of continuity equations and... more
Spectral response of GaAs solar cell is analytically computed incorporating the existence of quasi-Fermi level generated after photon shower. Analytical computation is carried out for simultaneous solution of continuity equations and diffusion equations, and contribution of drift is also taken into account. Results are obtained by varying structural parameters within lower photon energy range to obtain higher response magnitude.
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Complete electromagnetic bandgap is analytically computed for parallel nanorod structure when placed inside a triangular lattice in symmetric fashion. Being a metamaterial or double negative refractive index material, this structure... more
Complete electromagnetic bandgap is analytically computed for parallel nanorod structure when placed inside a triangular lattice in symmetric fashion. Being a metamaterial or double negative refractive index material, this structure exhibits tunable bandgap when dimension of the cylinder, i.e., fill factor of the structure is changed within feasible mechanical limit. Formation of bandgap becomes only possible for magnetic polarization, whereas even quasi bandgap is not observed for electric polarization. Maximum bandgap width is obtained for 0.45 value of normalized radius of the nanorod, and corresponding midband frequency is computed. Field patterns are also obtained for the desired frequency values. Maximum and minimum bandgap inside first Brillouin zone is calculated which plays critical role for photonic filter design.
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Characteristic impedance of MIM surface plasmon structure is analytically computed from the knowledge of propagation vector variation for different nanometric structural dimensions. Length, width, and distance between metal plates are... more
Characteristic impedance of MIM surface plasmon structure is analytically computed from the knowledge of propagation vector variation for different nanometric structural dimensions. Length, width, and distance between metal plates are kept in nanometer range to evaluate the propagation vector in high frequency domain, and effect of both Faraday inductance and kinetic inductance are incorporated. Notch in impedance profile is observed due to the modulation of surface plasmon propagation vector w.r.t dielectric propagation vector, and position of notch can suitably be tailored by proper choice of dimensions and material. Result provides accurate indirect measurement of the skin depth of the structure.
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Characteristic impedance of MIM surface plasmon structure is analytically computed from the knowledge of propagation vector variation for different nanometric structural dimensions. Length, width, and distance between metal plates are... more
Characteristic impedance of MIM surface plasmon structure is analytically computed from the knowledge of propagation vector variation for different nanometric structural dimensions. Length, width, and distance between metal plates are kept in nanometer range to evaluate the propagation vector in high frequency domain, and effect of both Faraday inductance and kinetic inductance are incorporated. Notch in impedance profile is observed due to the modulation of surface plasmon propagation vector w.r.t dielectric propagation vector, and position of notch can suitably be tailored by proper choice of dimensions and material. Result provides accurate indirect measurement of the skin depth of the structure.
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Characteristic impedance of MIM surface plasmon structure is analytically calculated considering the effect of both Faraday inductance and kinetic inductance. Effect of metal layer thickness, insulator thickness and electron density are... more
Characteristic impedance of MIM surface plasmon structure is analytically calculated considering the effect of both Faraday inductance and kinetic inductance. Effect of metal layer thickness, insulator thickness and electron density are tailored to observe the impedance variation with frequency. Detailed analytical calculation is made for impedance profile. Coupling between symmetric and antisymmetric modes are reflected by optimum impedance magnitude at very low frequency range, which effectively speaks for double sided surface plasmon. Results are immensely useful for spectroscopic applications.
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Input and output optical signal-to-noise ratio in 16-channel WDM network are investigated for predefined input noise level when design is set at minimum attenuation window. By keeping the input OSNR constant, gain and noise figure are... more
Input and output optical signal-to-noise ratio in 16-channel WDM network are investigated for predefined input noise level when design is set at minimum attenuation window. By keeping the input OSNR constant, gain and noise figure are computed along with SNR at both transmitting and receiving terminals for two different data rates and also with short-to-long range of trans-receiver distance. Corresponding variations of all the network properties, i.e., maximum Q-factor, eye height and noise figure are measured for estimation of performance degradation. Optimization in terms of both bit rate and channel distance is required, as evident from simulation result, for best possible system performance. Setting up of input noise level at 20 dBm indicates the fact of real-time compatibility with optimum value of output OSNR is revealed at a particular distance, which suggests the best result for communication system design.
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A preliminary investigation is carried out by applying Z-transform technique on different types of images with sole intention to record the z-score of any binary image. Bandwidth of the images are computed, and compared with that obtained... more
A preliminary investigation is carried out by applying Z-transform technique on different types of images with sole intention to record the z-score of any binary image. Bandwidth of the images are computed, and compared with that obtained from Fourier technique. Length of z-score matrix is graphically represented. Result is also analyzed for smooth, shiny and rough images. This preliminary investigation will help in sending multimedia content, precisely images through network and in signal processing which helps for the segments of cancerous portion.
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In this paper, millimeter-wave signals are generated with characteristics of high gain and low noise using optical frequency comb, where generated signals are tunable at a wider range (approx 50 GHz in both the sides) around the central... more
In this paper, millimeter-wave signals are generated with characteristics of high gain and low noise using optical frequency comb, where generated signals are tunable at a wider range (approx 50 GHz in both the sides) around the central frequency 94 GHz. Concept of electrical mixing is incorporated to achieve the tuning of the signals. Result shows that adopted methodology is far superior to conventional optical mixing and stable, high gain and low noise microwave signals are obtained in all the tuned frequencies. Wider tuning range speaks about the supremacy of the proposed scheme both in optical as well as in RF spectrum.
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From the advent of communication, there has been a constant demand for increasing communication capacity. In optical communications, capacity can be increased by implementing more fibers or can be increased by using the same fiber to... more
From the advent of communication, there has been a constant demand for increasing communication capacity. In optical communications, capacity can be increased by implementing more fibers or can be increased by using the same fiber to transmit more than one signal. The process is known as the wavelength division multiplexing or WDM. Channels placed closer to each other in the wavelength scale leads to the process of DWDM or dense WDM networks. But with so many channels transmitted together over minimum distances of 10 km, the power of each channel decreases significantly within the fiber, hence a Raman amplification system has been incorporated within the network. The whole system is designed at the 1300 nm optical window which has shown the least dispersion among the other optical windows. Results from simulating a 16 channel network with 8 optical pumps, where all are configured in co and counter propagating directions. They have shown good amount of gain, relatively low noise and ...
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N atural language processing is a widely used technique by which systems can understand the instructions for manipulating text or speech. In the present paper, a Text-to-speech synthesizer is developed that converts text into spoken word,... more
N atural language processing is a widely used technique by which systems can understand the instructions for manipulating text or speech. In the present paper, a Text-to-speech synthesizer is developed that converts text into spoken word, by analysing and processing it using Natural Language Processing (NLP) and then using Digital Signal Processing (DSP) technology to convert this processed text into synthesized speech representation of the text. Here we developed a useful text-to-speech synthesizer in the form of a simple application that converts inputted text into synthesized speech and reads out to the user which can then be saved as an mp3 file.
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Modulation response of GaAs quantum well laser is analytically investigated at microwave to millimeterwave operative frequency region. Effect of gain compression parameter is taken into account for calculating the response function, and... more
Modulation response of GaAs quantum well laser is analytically investigated at microwave to millimeterwave operative frequency region. Effect of gain compression parameter is taken into account for calculating the response function, and the work is centered around $1.55 \mu \mathrm{m}$. Confinement factor, mirror reflectivity and scattering effect inside the cavity are varied within practical limit to determine the blueshift of peak of response curve. Width of quantum well changes the wavelength of emitted wavelength, and that changes the modulation feature of the device. Threshold of all the tuning parameters are obtained after which the curve becomes flat, which is the limiting condition. Result will play key role in determining its efficiency as optical transmitter when coupled with optical fiber.
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The chapter deals with effective implementation of outcome-based education following Washington accord through activity-based teaching-learning system with a comparative study with the results obtained from conventional input-output... more
The chapter deals with effective implementation of outcome-based education following Washington accord through activity-based teaching-learning system with a comparative study with the results obtained from conventional input-output system. Effective implementation of this new pedagogical concept blended with technological tools is reflected through radical change while looking at the performance of the students in view of assimilation of knowledge vividly reflected through their industrial and academic placements. Result can be summarized in the form of more engagement in ABTLS which enhances the probability of acquaintance, thanks to the industry-mapped curriculum. Project-based learning in individual and group form increases the design and problem-solving skill, and requirement of industry is better satisfied. Achievement towards program outcome (PO) helps to produce better human resource in the context of present socio-humanitarian aspect and explores areas of further dynamic mo...
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Sarcasm detection in written texts is the Achilles’ heel of research areas in sentiment analysis, especially with the absence of the rightful verbal tone, facial expression or body gesture that leads to random misinterpretations. It is... more
Sarcasm detection in written texts is the Achilles’ heel of research areas in sentiment analysis, especially with the absence of the rightful verbal tone, facial expression or body gesture that leads to random misinterpretations. It is crucial in sectors of social media, advertisements and user feedbacks on services that require proper interpretation for service evaluation and improvisation of their products. The objective here thereby is to identify sarcasm within a given text by experimenting with the original predicted mood of the text and work on its transformation with the several variations in combination of the standard sarcastic elements present in the corresponding writing. Here standard NLP techniques are used for identification and interpretation. This involves detecting primary connotation of the given text (e.g. positive/neutral/negative), followed by detecting elements of sarcasm. Then, under the presence of the sarcasm indicator algorithm, the rightful interpretation ...
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Text-to-Braille conversion as well as speech-to-Braille conversion are not available in combined form so far for the visually impaired, and there is tremendous need of a device that can look after this special class of people. The present... more
Text-to-Braille conversion as well as speech-to-Braille conversion are not available in combined form so far for the visually impaired, and there is tremendous need of a device that can look after this special class of people. The present chapter deals with a novel model that is designed to help both types of impaired people, be it visual problem or related with hearing. The proposal is itself unique and is also supported by experimental results available within the laboratory condition. This device will help people to read from text with their Braille language and will also help to convert the same form to audio signal. Since text and audio are the two main interfaces for any person to communicate with the external world apart from functionalities of sensory organs, the work has relevance. With the help of DANET, the same data, in text or speech form, can be accessed in more than one digital device simultaneously.
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Electrical parameters of high-K based single gate nanoscale MOSFET is analytically computed considering the cylindrical geometry of the device. The paper’s novelty lies in the consideration of practical geometry of the channel rather than... more
Electrical parameters of high-K based single gate nanoscale MOSFET is analytically computed considering the cylindrical geometry of the device. The paper’s novelty lies in the consideration of practical geometry of the channel rather than conventional ideal rectangular one; for which drain current, transconductance, quantum capacitance, subthreshold swing and DIBL are calculated using Green’s function formalism under the ballistic limit. Results are compared with that obtained for identical input parameters when conventional low-K dielectric is used. Thickness of the cylindrical channel is tailored within 10 nm to analyze the variation of device parameters; and this tuning is experimentally possible as cylindrical geometry is considered instead of conventional rectangular potential profile. Remarkable improvements are obtained by virtue of lower subthreshold swing and DIBL; and lower channel thickness speaks in favor of higher transconductance and quantum capacitance.
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In this chapter, the importance of optimization technique, more specifically metaheuristic optimization in banking portfolio management, is reviewed. Present work deals with interactive bank marketing campaign of a specific Portugal bank,... more
In this chapter, the importance of optimization technique, more specifically metaheuristic optimization in banking portfolio management, is reviewed. Present work deals with interactive bank marketing campaign of a specific Portugal bank, taken from UCI dataset archive. This dataset consists of 45,211 samples with 17 features including one response/output variable. The classification work is carried out with all data using decision tree (DT), support vector machine (SVM), and k-nearest neighbour (k-NN), without any feature optimization. Metaheuristic genetic algorithm (GA) is used as a feature optimizer to find only 5 features out of the 16 features. Finally, the classification work with the optimized feature shows relatively good accuracy in comparison to classification with all feature set. This result shows that with a smaller number of optimized features better classification can be achieved with less computational overhead.
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In this paper, effect of temperature due to Joule heat dissipation in the optoelectronic circuit on the transmittivity and ripple in passband of the optical filter is analytically computed for normal incidence of electromagnetic wave. The... more
In this paper, effect of temperature due to Joule heat dissipation in the optoelectronic circuit on the transmittivity and ripple in passband of the optical filter is analytically computed for normal incidence of electromagnetic wave. The filter is made by photonic crystal with semiconductor heterostructure as the unit of periodic structure, and transfer matrix technique is used to determine the transmittivity of the filter around 1550 nm. Result suggests that external temperature has a great influence on the ripple in the desired passband as well as the structural parameters; and hence performance of this type of filter will greatly depend on the circuit conditions. However, bandwidth of the device remains unaffected in the temperature range considered. Results are useful for utilizing the device in all-optical integrated circuit and also to fabricate Bragg grating based sensor.
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In this paper, transmittance property of n-layer metal-insulator-metal surface plasmon structure is analytically investigated in the visible range of electromagnetic spectrum. Here n-layer signifies the critical number of layers after... more
In this paper, transmittance property of n-layer metal-insulator-metal surface plasmon structure is analytically investigated in the visible range of electromagnetic spectrum. Here n-layer signifies the critical number of layers after which increase in layer number insignificantly modifies the photonic behavior of the structure. Corresponding field enhancement is also computed to study the critical dimensions and external incident angles for maximum energy reflection. Peak in transmittance spectra is calculated when propagation constant of plasmon surface and that of incident wave becomes nearly equal. Results will help to detect biological nano-objects whose signature viruses have the same wavelength when transmittance peak occurs.
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The present paper deals with the classification problem of metamaterial-based photonic crystal from its band-pass filter characteristics obtained experimentally in presence and absence of defects at optical communication spectrum of 1.55... more
The present paper deals with the classification problem of metamaterial-based photonic crystal from its band-pass filter characteristics obtained experimentally in presence and absence of defects at optical communication spectrum of 1.55 µm. Two well-known DNG materials namely paired nanorod (n = −0.3) and nano-fishnet with elliptical void (n = −4) are considered for analysis purpose, and presence of point defects is taken into account in otherwise ideal structure which makes it as a four-class problem. Band-pass filter characteristics are measured for all the classes for both normal and oblique incidences separately with dimensional and incident angle variations; different soft computing techniques are applied for classification purpose as it is hardly possible to identify the device from the filter behavior. Apriori algorithm is utilized for association analysis to determine 100% confidence. Result shows that 98.53% accuracy is provided with neural network-based classifier with 98.93% sensitivity and 98.08% specificity when computation is made over 1000 samples.
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Finite Difference Time Domain (FDTD) method is utilized for modeling the optical pulse propagation in two-dimensional Kerr nonlinear dispersive medium. Through our investigation, spacio-temporal propagation owing to the nonlinear effect... more
Finite Difference Time Domain (FDTD) method is utilized for modeling the optical pulse propagation in two-dimensional Kerr nonlinear dispersive medium. Through our investigation, spacio-temporal propagation owing to the nonlinear effect is exhibited through modal analysis; and corresponding pulse broadening effects are displayed as a combined result of temporal dispersion and spatial diffraction. Simulation is carried out using opti-FDTD software. 1330 nm wavelength is considered for the present study, which is theoretically distortionless; however, still demonstrate the dispersive nature owing to the Kerr effect. With high intensity pumping, both TE and TM modes are plotted along with the computation for energy flow. Results are important for designing aperiodic lens and for optical switching.
Characteristic Lowest photonic bandgap width is analytically computed for double negative index materials from dispersion relation under propagation of TE wave. Three well-established metamaterials are considered for simulation purpose,... more
Characteristic Lowest photonic bandgap width is analytically computed for double negative index materials from dispersion relation under propagation of TE wave. Three well-established metamaterials are considered for simulation purpose, and two lower photonic bandgaps are computed with varying incidence angle for a few materials. Results are compared with existing bandgap widths obtained for positive refractive indices based materials. Results suggest that negative index materials offer higher bandgap width than existing positive index materials, and hence may be considered as better candidate for optical filter design.
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Two lowermost photonic bandgaps for one-dimensional photonic crystal are computed from dispersion relation. AlxGl1-xN/GaN material is considered for simulation purpose, and material composition is changed to calculate the shift of midband... more
Two lowermost photonic bandgaps for one-dimensional photonic crystal are computed from dispersion relation. AlxGl1-xN/GaN material is considered for simulation purpose, and material composition is changed to calculate the shift of midband frequency corresponding to the photonic bandgap. Both TE and TM polarizations are considered for bandgap computation, and results are evaluated from the first principle analysis. Calculations are made in normalized scale, and thus it can be fitted in the desired frequency spectrum when calculated from plane wave expansion method. Findings are utilized for design of optical filter.
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Peak tunneling current density in AlxGa1−xAs/GaAs/AlyGa1−yAs based resonant tunneling diode (RTD) is analytically computed using self-consistency technique. Simulation is carried out for different structural parameters and material... more
Peak tunneling current density in AlxGa1−xAs/GaAs/AlyGa1−yAs based resonant tunneling diode (RTD) is analytically computed using self-consistency technique. Simulation is carried out for different structural parameters and material systems within fabrication limit keeping the band structure type-I for the either sides of any quantum well, and peak value is estimated from the oscillating current density profiles. Temperature is also varied to observe the effect on peak current within tolerable limit. Effect of asymmetric material composition is also incorporated. Result is significantly pertinent for low bias applications where higher current is required, which can be obtained for nanometric device dimensions.
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Abstract In this chapter, the principal component analysis technique along with confusion matrix formation using a K-means clustering algorithm are applied to sensitive medical images for segmentation of cancerous portions through a... more
Abstract In this chapter, the principal component analysis technique along with confusion matrix formation using a K-means clustering algorithm are applied to sensitive medical images for segmentation of cancerous portions through a threshold detection procedure. Tumor present in the cancerous image with respect to the percentage of occupied portions by the tumor cells is predicted based on a predefined threshold level (cut-off level), where simulated findings have shown better performance than those obtained using the Otsu threshold method. This statement is established by comparison of the peak signal-to-noise ratio, and for better comparison, an edge detection operation is carried out on the image based upon the Canny algorithm. To segment sensitive medical images it is preferable to use a segmentation technique with high accuracy and precision, otherwise there is a possibility of losing valuable information about the cancer cells present in the image. For this, principal component analysis is used, where image assessment parameters play a significant role in diagnosing the image. Comparative analysis based on probability calculation, principal component coefficient, principal component score, eigenvalue matrix, centered data, and multiplicities matrix determine with better accuracy whether the specific segmented image is malignant in nature. These results have significant superiority over existing published data.
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Abstract A high-temporal resolution model for the identification of columnar aerosol composition was applied to two sets of radiometric measurements obtained one in a semi-rural site of South Italy and the other in an urban/traffic site... more
Abstract A high-temporal resolution model for the identification of columnar aerosol composition was applied to two sets of radiometric measurements obtained one in a semi-rural site of South Italy and the other in an urban/traffic site of the Po Valley, northern Italy. Inputs of the model are the spectral Aerosol Optical Depths (AODs) from direct solar radiation data to derive the contribution to the total extinction of nine aerosol species, i. e Water Soluble (WS), Black Carbon (BC), Sea Salt accumulation (SSacc), Sea Salt coarse (SScoa), Biogenic (Bio), Mineral Coarse (Mcoa), Mineral Accumulation (Macc), Small Organic Matter (SOM), and Large Organic Matter (LOM). In order to better parameterize the absorptive properties of dust and organic particles, a wavelength dependent imaginary part of the refractive index was used for dust and organics. Despite the differences between the two sites, a prevalence of fine aerosols (organics, WS and BC) was found in both cases suggesting the relevance of anthropogenic sources such as traffic. The retrieved AOD BC component was compared to Equivalent BC (EBC) concentrations measured in situ by an aethalometer at both sites. For mean daily values good correlations were found (R2 = 0.7), whereas high-temporal resolution (hourly basis) columnar composition was verified to be more reliable in cases of surface-column coupling. The possibility to apply this simple model to direct irradiance data from portable radiometers in areas where no routine measurements are available, and obtaining results with an increased temporal resolution, can help to gather information on aerosol columnar composition to be used in radiative, climate and transport models.
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ABSTRACT Reflection coefficient and full-width-half-maximum (FWHM) of a vertical cavity surface emitting laser are numerically computed by independently varying the well and barrier dimensions and material composition of the barrier layer... more
ABSTRACT Reflection coefficient and full-width-half-maximum (FWHM) of a vertical cavity surface emitting laser are numerically computed by independently varying the well and barrier dimensions and material composition of the barrier layer of the multiple quantum well embedded in the active region of the device. Reflection coefficient is calculated as a function of operating wavelength considering 1550 nm as central value for optical communication using propagation matrix method. Refractive indices of the MQW materials are considered as function of bandgap, operating wavelength and material composition following Adachi's model. The notable feature arises from the analysis is that suitable tuning of structural parameters can make it a bandpass or bandrejetct filter, which can be quantitatively computed form magnitude of FWHM. A nanometer bandwidth speaks for bandpass filter, whereas picometer range tells for its band-reject characteristics. No of layers in the MQW also controls the filter characterisitcs. Simulated results can be utilised to design VCSEL as optical transmitter in desired spectrum.
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This chapter is proposed with an approach to analyze reflectance as a function of negative index material thickness for different parameters under the surface plasmon condition and extended approach towards the field enhancement of... more
This chapter is proposed with an approach to analyze reflectance as a function of negative index material thickness for different parameters under the surface plasmon condition and extended approach towards the field enhancement of electric field as function of incidence angle and transmittance as function of incidence angle has been analyzed. This chapter can reflect the good comparison between 3 layer medium and n layer medium model. Characteristic impedance of MIM surface plasmon structure is analytically calculated considering the effect of both Faraday inductance and kinetic inductance. Effect of metal layer thickness, insulator thickness, and electron density are tailored to observe the impedance variation with frequency. Wavelength dependence of characteristic impedance and quality factor of MIM (metal-insulator-metal) surface plasmon structure is analyzed. Structural parameters and damping ratio of the structure is tuned within allowable limit to analyze the variation after ...
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An analytical method is presented to compute bit error rate and crosstalk in Fiber Bragg Grating based wavelength division multiplexing (WDM) network for estimating system performance. Different channel and device parameters are suitably... more
An analytical method is presented to compute bit error rate and crosstalk in Fiber Bragg Grating based wavelength division multiplexing (WDM) network for estimating system performance. Different channel and device parameters are suitably varied within moderate input power range (15 dBm), and effect of adjacent and non-adjacent channels are also calculated. Effect of number of bits on bit error rate is studied for a wider range of SNR, and result is compared with the ideal theoretically obtained result considering BPSK modulation technique. Detector responsivity of the device is considered to analyze crosstalk for maximum 10 no. of channels. Observations are important for calculating power penalty in optical communication system.
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Transmittance of one-dimensional photonic multiple quantum well structure is numerically computed using transfer matrix technique for normal and oblique incidence of p-polarized electromagnetic wave. Dimensional configuration and material... more
Transmittance of one-dimensional photonic multiple quantum well structure is numerically computed using transfer matrix technique for normal and oblique incidence of p-polarized electromagnetic wave. Dimensional configuration and material composition of the structure is varied to observe the modulation in filter bandwidth at 1550 nm for optical communication purpose. AlxGa1-xN/GaN composition is chosen as unit block of the periodic organization, with AlxGa1-xN layer as the barrier and GaN as well of the 11-layer structure. Refractive index of AlxGa1-xN is considered as a function of mole fraction and operating wavelength following Adachi’s model. Material having lower refractive index possesses greater width in lateral dimension compared to that of the material having higher refractive index. Variation of incident angle of p-polarized wave along with suitable choice of slab thicknesses and Al mole fraction makes it efficient band-pass filter at desired frequency region.
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Transmittivity of Al x Ga 1-x N/GaN based photonic multiple quantum well is numerically computed for normal and oblique incidences of electromagnetic wave with p-polarization condition. Transfer matrix technique is used to observe the... more
Transmittivity of Al x Ga 1-x N/GaN based photonic multiple quantum well is numerically computed for normal and oblique incidences of electromagnetic wave with p-polarization condition. Transfer matrix technique is used to observe the shift of optical filter bandwidth centered around 1.55 μm by varying structural parameters. Al x Ga 1-x N and GaN layers are considered as barriers and well respectively, and refractive index of Al x Ga 1-x N is considered as a function of mole fraction and operating wavelength following Adachi's model. Results are compared with conventional SiO 2 /air photonic crystal with similar size and layers. Increasing no. of layers makes it more effective filter by increasing reflectivity outside the desired region of interest. Material composition has a profound effect on the filter performance. Study reveals that efficient bandwidth tuning can be made for semiconductor heterostructure based device.
Band structure and electron density of states of single-wall zigzag carbon nanotube are analytically computed using nearest neighbor tight binding (NNTB) approximation and theory of linear combination of atomic orbitals (LCAO). DOS is... more
Band structure and electron density of states of single-wall zigzag carbon nanotube are analytically computed using nearest neighbor tight binding (NNTB) approximation and theory of linear combination of atomic orbitals (LCAO). DOS is calculated by varying cylindrical dimension, lattice index and neighboring atomic distance. Results show that magnitude of peak of DOS increases with decreasing radius of the tube, lowering bandgap and decreasing of nearest neighbor distance. Wave-vector dependent Hamiltonian is calculated by solving time-independent Schrödinger equation to study band structure. Bandgap is also computed for the two lowest modes only as a function of nearest neighbor distance for different semiconducting tubes. With increase of distance between neighboring atoms and decreasing lattice index, bandgap of semiconducting nanotube linearly increases. For higher order mode, bandgap increases with significant rate compared to the lowest mode. Results can be utilized in develop...
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— In this paper, reflective coefficient due to electromagnetic wave propagation in forward and backward directions inside one-dimensional photonic crystal is analytically computed using coupled mode theory for varying coupling... more
— In this paper, reflective coefficient due to electromagnetic wave propagation in forward and backward directions inside one-dimensional photonic crystal is analytically computed using coupled mode theory for varying coupling coefficients and different material compositions. Grating length is tuned for near accurate study of the stratified periodic structure. The periodic dielectric array is essentially Bragg grating where increase in grating length enhances the reflection of electromagnetic wave, and strong coupling provides larger bandgap spectral width. For simulation purpose, GaN/AlxGa1-xN material composition is considered as unit block of the periodic organization, and refractive indices of materials are taken as function of bandgap and operating wavelength following Adachi’s model. Results are compared with that obtained for SiO2/air system for identical structural parameters and other propagating conditions. Simulation proves the dominance of usability of semiconductor hete...
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In this paper, a comparative analysis is made for density of states function of one-dimensional finite photonic crystal for both s and p-polarized wave incidences with different material compositions. Computation is carried out for... more
In this paper, a comparative analysis is made for density of states function of one-dimensional finite photonic crystal for both s and p-polarized wave incidences with different material compositions. Computation is carried out for AlxGa1-xN/GaN heterostructure, and results are compared with conventional SiO2/Air composition. Structural parameters of the periodic arrangement are suitably varied to observe the effect on the density of states, and observations are graphically represented by blueshift and redshift. For the AlxGa1-xN/GaN material composition, Adachi’s model has been considered to incorporate the dependencies of refractive indices on operative wavelength and material composition. Occurrence of the peak positions in both the cases speaks about the possible emission/detection wavelength range and shows the superiority of the semiconductor heterostructure based composition in fabricating a photonic crystal based optical transmitter/receiver.
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Bandgap width within first Brillouin zone in metamaterial-based two-dimensional photonic crystal structure is analytically computed using plane wave expansion method. A wider range of negative refractive index is considered for simulation... more
Bandgap width within first Brillouin zone in metamaterial-based two-dimensional photonic crystal structure is analytically computed using plane wave expansion method. A wider range of negative refractive index is considered for simulation purpose within physically feasible limit whereas rectangular geometrical shape is taken into account for the analysis with TE mode of propagation. Artificial materials in presence of air holes are considered to achieve negative index, and results are compared with that obtained for conventional SiO2-air material system with equivalent dimensional configuration. Coordinates of two peak points, $\hbox{`}\Gamma\hbox{'}$ point and ‘X’, point are noted for all the DNG materials which give the indication of blueshift of the valence region with change of negative refractive index. Simulated findings speak in favor of multiple forbidden regions for some specific material systems which can be utilized to design photonic multi-channel filter in beyond TH...
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In unbounded media, wave propagation is supposed to be unguided. The existence of uniform plane wave is considered to be all through the space. Electromagnetic energy related with the wave stretched over a broad area. In TV and radio... more
In unbounded media, wave propagation is supposed to be unguided. The existence of uniform plane wave is considered to be all through the space. Electromagnetic energy related with the wave stretched over a broad area. In TV and radio broadcasting, unbounded medium propagation of the wave is required. Here transmission of information is destined for one and all who may be interested. Another way of transmitting information is by guided media. Guided media acts to direct the transmission of energy from transmitter to receiver. Transmission lines are usually used in low frequency power distribution and in high frequency communications as well as in the ethernet and internet in computer networks. Two or more parallel conductors may be used to construct a transmission line, which connects source to a load. Typical transmission lines consist of coaxial line, waveguide, microstrip line, coplanar waveguide, etc. In this chapter, problems related with transmission lines are solved with the h...
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In this paper, gate-induced-drain-leakage current due to band-to-band tunneling is analytically computed in nanometric MOSFET under high electric field. Fowler-Nordheim tunneling current is first calculated for different dielectric... more
In this paper, gate-induced-drain-leakage current due to band-to-band tunneling is analytically computed in nanometric MOSFET under high electric field. Fowler-Nordheim tunneling current is first calculated for different dielectric thicknesses with some alteration of Hu’s model, and dominance of thermionic current is established. Under this criterion, B–B tunneling current is evaluated as leakage arises due to the overlap of gate over source and drain regions, and dielectric properties along with doping concentration and temperature are taken into account following Kane’s tunneling probability. Role of high-K dielectric material is also analyzed for nanoscale application. Result shows that higher overlapping of gate length due to lateral diffusion of source and drain regions tailors the leakage current. Findings are extremely important for use of the device as SRAM.
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Transfer characteristics of single electron transistor are analytically worked out as function of different tunneling parameters. Source and drain are quantum mechanically coupled by quantum dot for carrier transport, and tunneling... more
Transfer characteristics of single electron transistor are analytically worked out as function of different tunneling parameters. Source and drain are quantum mechanically coupled by quantum dot for carrier transport, and tunneling mechanism is taken as stochastic in nature. Tunneling probabilities and corresponding free energy changes are computed using Fermi Golden Rule (FGR). Equivalent circuit parameters are tuned within appreciable limit to find out the dependence of drain current on gate bias. Results are important for computing transconductance of the device.
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In this paper, tunneling current in nanoscale MOSFET is analytically investigated using BSIM4 model for very low power VLSI applications. Simulation is carried out for low and high electric fields separately, and appropriate mathematical... more
In this paper, tunneling current in nanoscale MOSFET is analytically investigated using BSIM4 model for very low power VLSI applications. Simulation is carried out for low and high electric fields separately, and appropriate mathematical equations are formulated for that purpose by modifying the existing model proposed by Hu. Effect of dielectric thickness and internally generated electrical parameter variations are measured on tunneling current. Diode-like behavior under the application of high field speaks about the magnitude of critical field where thermionic current starts to dominate. Results are critically important for non-volatile memory applications.
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Dependence of conductance on equivalent circuit parameters in single electron transistor is analytically computed for electrical performance estimation. Distorted conductance profiles are obtained when a few passive components exceeds... more
Dependence of conductance on equivalent circuit parameters in single electron transistor is analytically computed for electrical performance estimation. Distorted conductance profiles are obtained when a few passive components exceeds threshold limit, and negative spikes are also possible, as revealed from simulation. Steady-state master equation is solved with appropriate boundary conditions when source and drains are connected via quantum dot, which ensures tunneling process. Fermi Golden Rule is applied to calculate probabilistic values of all stochastic processes and effect of source and drain resistances and capacitances as well as gate capacitance are considered for determining conductance. Simulated findings are important for practical application of SET as infrared detector and charge sensor.
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Optical bandwidth of defected ternary photonic crystal is analytically computed under oblique incidence. P-polarized is considered for incidence on the structure, and result is compared with that obtained under normal incidence.... more
Optical bandwidth of defected ternary photonic crystal is analytically computed under oblique incidence. P-polarized is considered for incidence on the structure, and result is compared with that obtained under normal incidence. Intentionally defect is incorporated within feasible limit for narrow bandpass filter design; and layer dimension is tuned to observe the variation around 1550 nm. It is observed that passband with ripple can suitably be tailored by varying the defect density. Critical dimension is predicted for different layers over which the effect of sandwiched layer becomes insignificant, i.e., the structure will behave as binary one. Result is important for design of filter when noise spectrum is closely spaced with desired signal for optical communication.
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37 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: B0129111111 /2011©BEIESP Abstract— Transmission probability of a parabolic double quantum well triple barrier structure in presence of finite... more
37 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: B0129111111 /2011©BEIESP Abstract— Transmission probability of a parabolic double quantum well triple barrier structure in presence of finite thick contact barriers is computed using propagation matrix method for GaAs/AlxGa1-xAs material composition. This provides the idea of tunneling at energies less than barrier potential. Effect of different barrier thicknesses and well widths are independently studied on transmission coefficient, and also for a specified structure, material composition of barriers is varied to observe the tunneling effect. Propagation matrix method is used for simulation purpose, and computation is performed considering effective mass mismatch at junctions following BenDaniel Duke boundary conditions. Conduction band discontinuity is also incorporated in the analysis by virtue of that consideration. Contact and middle barrier widths are varied for the same composition...
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Effective object detection must be able to handle cluttered visions which convert into the object size, location, orientation, and other movements. We presumed that Computer Vision System Toolbox™ MathWorks offers a variety of techniques... more
Effective object detection must be able to handle cluttered visions which convert into the object size, location, orientation, and other movements. We presumed that Computer Vision System Toolbox™ MathWorks offers a variety of techniques for handling challenges in object detection. In this paper, we elaborate on how to detect an object in a cluttered scene, given a reference image of the object. The output of this paper explains an algorithm for detecting a recognized object depending on finding the vision points correspondences between reference and target images. It can detect each and every object in spite of a scale change or in-plane rotation and quite extend to robust with small amounts of out-of-plane rotation. This method of object detection through recognized feature points works best for objects that exhibit non-repeating texture patterns, which give rise to unique feature matches. In connection with this, present algorithm is designed for detecting a specific static objec...
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A fast squaring technique for the operands nearer to a particular radix is reported in this paper. The technique offers significantly less computational complexity which reduces the processing time to a large extent. Considering the... more
A fast squaring technique for the operands nearer to a particular radix is reported in this paper. The technique offers significantly less computational complexity which reduces the processing time to a large extent. Considering the applicability of the technique for a particular set of numbers which are in the vicinity of the corresponding radix, it is shown that the technique is equally acceptable for very large radix number. The proposed approach has been verified using Xilinx ISE Vertex-7 FPGA device. Simulated findings showed that with a significant increment in radix value (99.87%), the change of propagation delay is extremely small (2.33%), and corresponding increase in power dissipation is within tolerable range (29.84%). The results show the improvement in speed and computational complexity.
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In this paper, a comprehensive review work is carried out on numerical analysis for transmittivity of onedimensional due to its immense applicability in photonic integrated circuit. Detailed literature survey is made for analyzing the... more
In this paper, a comprehensive review work is carried out on numerical analysis for transmittivity of onedimensional due to its immense applicability in photonic integrated circuit. Detailed literature survey is made for analyzing the tuning possibility of proposed bandpass filter by this structure for both normal and polarized incidence of electromagnetic wave. Structural parameters are also modified within the suitable range considering practical limit for study of the shift of passband around centered wavelength. Brief mathematical modeling is also presented, and a few works of the authors in this regard are added, which speaks for the importance of the present state of work. By highlighting the significant development in the field of photonic circuit through the implementation of photonic crystal, this paper aims to present the overall technical details carried out by eminent researchers in a short brief method. KeywordsTransmittivity; One-dimensional photonic crystal; Bandpass ...
Cancerous cells are detected by affine transformation by working on multi-resolution, multi-lateral, multi-cluster image patterns for prediction analysis. Accuracy, sensitivity and specificity of a few images are calculated for the... more
Cancerous cells are detected by affine transformation by working on multi-resolution, multi-lateral, multi-cluster image patterns for prediction analysis. Accuracy, sensitivity and specificity of a few images are calculated for the affected cells, where results provide less confusion value of transformed images than the originals. Authenticity of the cell is investigated by computing true and false positive and negative rates. Difference in maximum peak amplitude for Z-transformed image and Z-transformed affine image is calculated to evaluate the importance of the transform procedure. From the assessment of image, status of the cancerous cell can be easily revealed, whether it is benign or malignant, and the corresponding decision can be taken for shielding of other cells.
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Research Interests:
Novel band-reject filter is proposed using multilayer Bragg mirror structure by computing reflection coefficient at 1550 nm wavelength for optical communication. Dimension of different layers and material composition are modified to study... more
Novel band-reject filter is proposed using multilayer Bragg mirror structure by computing reflection coefficient at 1550 nm wavelength for optical communication. Dimension of different layers and material composition are modified to study the effect on rejection bandwidth, and no. of layers is also varied for analyzing passband characteristics. GaN/AlxGa1-xN composiiton is taken as the choice for simulation purpose, carried out using propagation matrix method. Refractive indices of the materials are considered as function of bandgap, operating wavelength and material composition following Adachi’s model. One interesting result arises from the computation that band-reject filter may be converted into band-pass one by suitably varying ratio of thicknesses of unit cell, or by varying Al mole fraction. Simulated results can be utilised to design VCSEL mirror as optical transmitter.
A numerical investigation of first two eigenenergy states of double quantum well triple barrier structure has been carried out considering GaAs/Al x Ga 1-x As material composition to estimate the probability of resonant tunneling in... more
A numerical investigation of first two eigenenergy states of double quantum well triple barrier structure has been carried out considering GaAs/Al x Ga 1-x As material composition to estimate the probability of resonant tunneling in presence and absence of electric field. The structure is made realistic by considering the finite thickness of contact barriers, and concept of effective mass mismatch is also incorporated to the solution of Schrodinger’s equation with variation of mole fraction of Al x Ga 1-x As material. This also leads to the potential asymmetric effect which is studied along with the independent effect of barrier width and well width variation, and consequence of modification of contact barrier thickness on energy eigenvalues is evaluated. Variation of mole fraction in presence of electric field provides a shift in eigenenergies for resonance transmission, and electric field increment suggests the existence of shift in eigenstates and corresponding modification of re...
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Eigenenergies of lowest three quantum states in semiconductor quantum ring is analytically determined as a function of surface-to-volume ratio subject to the application of external electric field applied along the axis of the ring, which... more
Eigenenergies of lowest three quantum states in semiconductor quantum ring is analytically determined as a function of surface-to-volume ratio subject to the application of external electric field applied along the axis of the ring, which is perpendicular to ring plane. n-GaAs material is considered for simulation, and the results are compared with that obtained in the absence of field. Result shows that with increasing S/V ratio, energy increases almost linearly in the presence of field, whereas the behavior is nonlinear when field is absent. Critical finding in this respect is that intersubband transition remains constant with increasing S/V ratio, which speaks about its candidature as optical emitter/detector within dimensional variation over nanorange. Variation is also calculated for different surface areas and volume of nanodevice. Result speaks about possible tuning of the eigenenergy by external field in IR wavelength region.
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The guiding structure which is to be considered for high frequency applications is Gap waveguide. Because of its numerous merits, this technology has become an astounding attraction to many investigators. Limited bandwidth is one of major... more
The guiding structure which is to be considered for high frequency applications is Gap waveguide. Because of its numerous merits, this technology has become an astounding attraction to many investigators. Limited bandwidth is one of major issue for designing the transition. This paper discusses an Inline transition between coaxial probe to Ridge gap waveguide in Ku and K band using Ansoft HFSS software. Using a simple inline coaxial probe transition a dual band characteristics has been observed with a bandwidth of 200 MHz. A modified L shape transition has been designed which shows 5GHz bandwidth with an overall return loss higher than 15dB and comparatively lower insertion less having magnitude less than 0.9dB been observed. In addition field distribution has been discussed.
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Filters in all-optical circuit have the potential advantage over that of optoelectronic circuits because of very high SNR, thanks to the reduced scattering between photons instead of electron-electron collisions. This property makes the... more
Filters in all-optical circuit have the potential advantage over that of optoelectronic circuits because of very high SNR, thanks to the reduced scattering between photons instead of electron-electron collisions. This property makes the PhC based filters as the blue-eyed candidate for optical signal processing in photonic circuits. Semiconductor heterostructures are in general the constituent element of photonic crystal (PhC) based devices, whose performance is characterized by passband width at the desired frequency of communication spectrum, along with magnitude of ripple in that region of interest. The present paper shows that effect of device temperature has a great deal of influence on the performance parameters of the filter, under different polarized conditions and different magnitudes of structural parameters within physically realizable limit. But modulation of bandwidth is negligibly small as observed from simulated results within the choice of temperature range. Results a...
38 www.erpublication.org Abstract— In this paper, density of states (DOS) profile of one-dimensional finite photonic crystal is analytically calculated under the incidence of p-polarized electromagnetic wave for AlxGa1-xN/GaN material... more
38 www.erpublication.org Abstract— In this paper, density of states (DOS) profile of one-dimensional finite photonic crystal is analytically calculated under the incidence of p-polarized electromagnetic wave for AlxGa1-xN/GaN material composition. For generalization, normalized wavelength range is considered, and structural parameters of periodic arrangement are varied to observe the effect on DOS function. Following Adachi’s model, refractive indices of the materials are considered as function of mole composition and operating wavelength. The position of density peaks indicates the possible emission/detection wavelength for photonic crystal based optical emitter/detector. Fine wavelength tuning by changing layer dimensions or material compositions is characterized by blueshift and redshift. The analysis presented in this paper will be useful in designing micro-laser and optical memory devices.
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Surface potential of lightly doped symmetric double-gate MOSFET is analytically evaluated using Ortiz-Conde model for different structural dimensions in nanometric range, and corresponding drain current is evaluated for lower region of... more
Surface potential of lightly doped symmetric double-gate MOSFET is analytically evaluated using Ortiz-Conde model for different structural dimensions in nanometric range, and corresponding drain current is evaluated for lower region of applied bias. The device dimension is considered in nanometer range, and due to light doping, the result of potential distribution exhibits increasing nature with gate voltage, where potential drop across dielectric layer is taken into account for realistic calculation. Pinch-off voltage dependence on material and structural parameters is estimated from static characteristics, and corresponding drain resistance is calculated. Simulated findings are very close to the previously obtained results. Result will help to design DG for low power application.
Objective of this paper is to primarily detect moving vehicles from real-time captured images so that we can later use them for a variety of purposes like detecting the number of vehicles that are present at a road at a certain point,... more
Objective of this paper is to primarily detect moving vehicles from real-time captured images so that we can later use them for a variety of purposes like detecting the number of vehicles that are present at a road at a certain point, understanding the motion of the vehicles, analyzing vehicle density at any traffic signal at any specified point of time; and based on our previous knowledge can make a good assumption where the vehicle will be heading towards. Signal-to-noise ratio, PSNER and mean-square-error are computed for each captured image using after detection. After establishing vehicle detection scheme, we can also make an attempt to read vehicle plate numbers further a much broader attempt to automate a traffic flow system using image recognition and probability distribution.
This chapter shows the measurement procedure of junction depth using SIMS method with detailed experimental procedure, and the result is verified by theoretical computation. SIMS profile is analytically characterized by Pearson's... more
This chapter shows the measurement procedure of junction depth using SIMS method with detailed experimental procedure, and the result is verified by theoretical computation. SIMS profile is analytically characterized by Pearson's distribution function, and all the results together established the fact that the device can be utilized for operating as a diode in RF range; where ion dose is considered as a variable parameter with ion energy. Implanted impurity distribution profile is obtained as a function of depletion width from which junction depth can be evaluated. Straggle parameters and projected range profile near the ion energy range is computed for which depth is evaluated, and skewness & kurtosis are estimated to get a theoretical knowledge of all the moments assuming the Pearson IV distribution. Results suggest that distribution of atoms may be considered as Gaussian in nature.
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A novel glucometer circuit is proposed in this manuscript with an in-built memory chip so that data of a patient can be continuously monitored for the level of glucose present in h(is/er) blood for the last 6 months. The potentiometric... more
A novel glucometer circuit is proposed in this manuscript with an in-built memory chip so that data of a patient can be continuously monitored for the level of glucose present in h(is/er) blood for the last 6 months. The potentiometric Si-based glucose sensor has the added advantage in terms of fabrication point-of-view owing to existing matured microelectronics technology, making it a low-cost device. With 66.3% of sensitivity and 726% higher ON current than the CNT-based glucose sensor as per available published data, the present system may exhibit better acceptability with matured fabrication techniques. Anyone can calculate the percentage changes with the reference level of glucose level, and therefore, we are able to find out the changes with respect to the previous data values. With an easy quantitative analysis, this prototype can easily be accessed by most of the people around the world irrespective of financial limitations.
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Effect of tunneling resistances and tunneling capacitances on the current-voltage characteristics of single electron transistor are analytically computed assuming source and drain ends are connected by quantum dot. Steady state master... more
Effect of tunneling resistances and tunneling capacitances on the current-voltage characteristics of single electron transistor are analytically computed assuming source and drain ends are connected by quantum dot. Steady state master equation is solved by considering tunneling mechanism a stochastic process, and free energy changes are calculated as a function of equivalent circuit parameters and background charge. Tunneling probabilities at drain and source ends are determined using Fermi's Golden Rule. Threshold values of all the circuit parameters are calculated below or above which degraded performances can be obtained.
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Electromagnetic wave propagation inside one-dimensional photonic crystal fiber is numerically characterized by computing V-parameter, cladding index and effective mode profiles. Dependence on these parameters on geometrical structure of... more
Electromagnetic wave propagation inside one-dimensional photonic crystal fiber is numerically characterized by computing V-parameter, cladding index and effective mode profiles. Dependence on these parameters on geometrical structure of the fiber reflects the design tolerance, and corresponding modal characteristics. Air-hole spacing and periodicity are varied to observe the effect on V-parameter; along with effective core radius, which is a function of periodicity, is modified to see the effect on cladding index and effective mode profiles. Results obtained from empirical relations method are compared with analytical formula of Nielsen and Mortensen. Periodicity of the structure is regarded as numerically equal to the central wavelength of the desired range throughout the computation. Refractive index of the core is taken as independent of operating wavelength. Simulated parameters have critical importance to estimate the characteristics of photonic crystal fiber which will help th...
Eigenstates of two different circular quantum dots (quantum ring and quantum disk) are analytically computed by solving time-independent Schrodinger equation in presence of transverse magnetic field. Intraband transition energy is... more
Eigenstates of two different circular quantum dots (quantum ring and quantum disk) are analytically computed by solving time-independent Schrodinger equation in presence of transverse magnetic field. Intraband transition energy is calculated for the lowest three states. Dimensions and magnitude of applied field are tuned to observe the effect on eigenstates and transition energies. Comparative studies for both eigenvalue and transition energies are made between the devices with similar size and under equal applied field. Results show that transition energy decreases with increasing device diameter, and increases with increase of magnetic field. Change in transition energy indicates the possibility of wavelength tuning by magnetic field for optical emitter/detector applications.
In this paper, reflective coefficient due to electromagnetic wave propagation in forward and backward directions inside one-dimensional photonic crystal is theoretically computed using coupled mode theory. Coupling coefficient and... more
In this paper, reflective coefficient due to electromagnetic wave propagation in forward and backward directions inside one-dimensional photonic crystal is theoretically computed using coupled mode theory. Coupling coefficient and material composition are varied to study the possible change in wave propagation in the bounded medium. Grating length is tuned for near accurate computation of the stratified periodic structure. The periodic dielectric array is essentially a Bragg grating where increase in grating length enhances the reflection of electromagnetic wave, and strong coupling provides larger bandgap spectral width. For simulation purpose, GaN/AlxGa1-xN material composition is considered as unit block of the periodic organization, and refractive index of AlxGa1-xN is taken as function of bandgap and operating wavelength following Adachi’s model. Results are compared with that obtained for SiO2/air material system for identical structural parameters and other propagating condit...
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In this paper, transfer matrix technique is used to compute the First Brillouin zone of DNG/air material composition for the application in photonic crystal. Three different types of physically realizable metamaterials are considered as... more
In this paper, transfer matrix technique is used to compute the First Brillouin zone of DNG/air material composition for the application in photonic crystal. Three different types of physically realizable metamaterials are considered as the constituent of the periodic arrangement. Tuning of the Brillouin zone is made by suitable changing the structural parameters and coupling coefficient between forward and backward propagating waves for all three structures (paired nanorod, nano-fishnet with rectangular void, nano-fishnet with elliptical void). Results obtained from the first principle show the possibility of transition between perfect and quasi electromagnetic bandgap which is important for the possible application as photonic filter. Result is compared with the obtained band structure of conventional SiO2/air composition.
ABSTRACT Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific... more
ABSTRACT Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific energy values less than barrier potential. Effects of different barrier width and well width on transmission coefficient are studied independently, and also for a specified structure, mole fraction for contact and middle barriers are independently varied to study transmission properties using transfer matrix technique. This also leads to the concept of variable effective mass which is incorporated in the solution of Schrödinger's equation, and comparative analysis is carried out for constant and variable effective mass in order to make the computation more realistic. Asymmetric potential effect on transmission coefficient is also observed by virtue of that consideration.
: Fill factor in the negative permittivity materials are tailored within physically permissible limit to characterize the Brillouin zone for two-dimensional crystal under propagation of both s and p-polarized waves. Two lowermost bandgaps... more
: Fill factor in the negative permittivity materials are tailored within physically permissible limit to characterize the Brillouin zone for two-dimensional crystal under propagation of both s and p-polarized waves. Two lowermost bandgaps are computed along with corresponding midband frequencies, where plane wave expansion method is invoked for computational purpose. Rectangular geometrical shape is considered for the simulation, and all the results are calculated inside the ‘Γ’ point and ‘X’ point of first Brillouin zone. Simulated findings depict monotonous variations of both bandgap width as well as midband frequency for higher negative permittivity materials, when magnitude of fill factor is comparatively low, for both TE (Transverse Electric)and TM (Transverse Magnetic)mode of propagations. Lower negative permittivity leads to random fluctuations which makes it unsuitable for photonic component design. Multiple forbidden regions may be observed for some specific artificial materials which can be utilized in antenna or multi-channel filter design in higher THz region. Aims: The present paper aims to compute the shape of the first Brillouin zone from the fill factor for a two-dimensional photonic crystal structure. Background: EBG (Electromagnetic Band gap) of a photonic crystal plays a major role in determining its candidature for optical applications, which is critically controlled by fill factor. Therefore, it is significant to investigate the effect of F.F on the wave propagation characteristics of 2D PhC(Two-dimensional photonic crystal). Objective: Investigation of metamaterial based photonic crystal structure for electromagnetic bandgap analysis in the desired spectrum of interest as a function of fill factor inside the first Brillouin zone Method:Maxwell’s equations are solved using plane wave propagation method to solve the problem, and simulation is carried out in MATLAB® software. Result: Both the first and second photonic bandgaps are simultaneously computed with variation of refractive index differences of the constituent materials as well as with the fill factors. Results are extremely significant about the formation of narrowband and wideband filters on certain material combinations and structural designs. Conclusion: Better tenability is observed for metamaterial structure compared to conventional positive index materials, and fill factor has a great role in shaping the Brillouin zone and corresponding bandgap width.
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Aim:: Computation of loss factors for one-bit RF MEMS switch over Ku, K and Ka-band for two different insulating substrates. Objective:: Numerical investigation of return loss, insertion loss, isolation loss are computed under both... more
Aim:: Computation of loss factors for one-bit RF MEMS switch over Ku, K and Ka-band for two different insulating substrates. Objective:: Numerical investigation of return loss, insertion loss, isolation loss are computed under both actuated and unactuated states for two different insulating substrates of the 1-bit RF MEMS switch, and corresponding up and down-capacitances are obtained. Methods:: The unique characteristics of a 1-bit RF MEMS switch of providing higher return loss under both actuated and unactuated states and also of isolation loss with negligible insertion loss makes it as a prime candidate for phase shifter application. This is presented in this manuscript with a keen focus on improvement capability by changing transmission line width, and also of overlap area; where dielectric constant of the substrate also plays a vital role. Results:: The present work exhibits very low down-capacitance over the spectrum whereas considerable amount of up-capacitance. Also when ove...
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: Two lowermost photonic bandgap widths of metamaterial-based one-dimensional photonic crystal are analytically computed from the dispersion relation under propagation of transverse electromagnetic wave along the direction of confinement.... more
: Two lowermost photonic bandgap widths of metamaterial-based one-dimensional photonic crystal are analytically computed from the dispersion relation under propagation of transverse electromagnetic wave along the direction of confinement. Three practically realizable double negative index materials are considered for computation of bandgaps, where air-gaps are considered along with the artificially made materials as the composite grating structure. This is a combination of negative-positive indices materials, where incident angles are tailored within practical limit to calculate the variation of bandgaps, which may be quasi or complete depending on the material composition and angle of incidence. Results are compared with that obtained for TE mode propagation, and are highly important for design of the all-optical filter with DNG materials. Aim: Calculation of dispersion profile and photonic bandgap for negative refractive index based one-dimensional photonic crystal structure. Objective: Determine mathematically the variation of first and second photonic bandgaps under angular incidence variation for the metamaterial-based 1D PhC structure for both TE and TM mode of propagations . Introduction: The unique feature of restricting electromagnetic wave propagation of specified spectra along the direction of refractive index variation in a grating-like structure becomes realizable by creating quasi or complete bandgap, termed as photonic bandgap. In the present paper, extents of two lowermost photonic bandgaps are theoretically analyzed under the consideration of TM mode propagation with a wider range of incidence angle variation, and result is compared with that when TE mode propagation is concerned. Results: Two lowermost photonic bandgap widths of metamaterial-based one-dimensional photonic crystal are analytically computed from the dispersion relation under propagation of transverse electromagnetic wave along the direction of confinement. Conclusion: For a wider angle of incident angle, 74.6% variations of first photonic bandgap are obtained for paired nanorod, almost 100% for fishnet with elliptical void, and 90.8% for fishnet with rectangular void is obtained; whereas mere 28.3% variation is seen for positive index material system. Interesting observation is found out for nano-fishnet structure with elliptical void, where first bandgap is absent for TM mode, but the second one is present.
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In this paper, transfer matrix technique for computing the band structure and transmittance of one dimensional photonic crystal is analyzed using group theoretical approach, and a novel algorithm is developed for that purpose to reduce... more
In this paper, transfer matrix technique for computing the band structure and transmittance of one dimensional photonic crystal is analyzed using group theoretical approach, and a novel algorithm is developed for that purpose to reduce the time for computation. The advantage of this algorithm is that it bypasses the implicit N times matrix multiplication that is performed by a digital computer when calculating the band structure of periodic dielectric structures consisting of N cells when N is moderately large. The formulation indicates that the simplified algorithm can significantly ease the numerical burden and reduce the requirement on computer memory space.
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Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific energy values... more
Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific energy values less than barrier potential. Effects of different barrier width and well width on transmission coefficient are studied independently, and also for a specified structure, mole fraction for contact and middle barriers are independently varied to study transmission properties using transfer matrix technique. This also leads to the concept of variable effective mass which is incorporated in the solution of Schrödinger's equation, and comparative analysis is carried out for constant and variable effective mass in order to make the computation more realistic. Asymmetric potential effect on transmission coefficient is also observed by virtue of that consideration.
Band structure of one-dimensional photonic crystal is analytically computed under the normal incidence of electromagnetic wave inside first Brillouin zone. Plane wave expansion method is applied on Maxwell’s equations, and set of... more
Band structure of one-dimensional photonic crystal is analytically computed under the normal incidence of electromagnetic wave inside first Brillouin zone. Plane wave expansion method is applied on Maxwell’s equations, and set of eigenvalues are computed for different momentum values. Helmholtz theorem is used along with Fourier transform method to obtain the direction of wave propagation inside the lattice, and size of the Hamiltonian is reduced due to the identical behaviour of TE and TM modes. Result is computed for AlGaN/GaN composition, and is compared with conventional SiO2/air material system. Result will be helpful to determine the dispersion relation of 1D photonic crystal, allowing us to design periodic photonic structures with required photonic bandgap. Knowledge may be utilized to design photonic crystal-based bandpass filter for use in photonic integrated circuit.
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An comparative study is performed for calculating the bandgap of one-dimensional photonic crystal structure using two widely used numerical methods, namely Transfer Matrix Method (TMM) and Plane Wave Expansion method (PWM). Numerical... more
An comparative study is performed for calculating the bandgap of one-dimensional photonic crystal structure using two widely used numerical methods, namely Transfer Matrix Method (TMM) and Plane Wave Expansion method (PWM). Numerical computation is carried out under different structural conditions and different operating wavelength spectrum for analysis purpose. Result reveals that TMM is specifically advantageous to some extent in the case of one dimensional photonic crystal, but we will see that it fails miserably in case of two and three dimensional structures which are characterized by complicated boundary conditions at their interfaces. Even for the one-dimensional case, with the increase in the number of periodic layers, the TMM method fails to approximate the band structure. The PWM method on the other hand is a relatively slow in terms of computation time but fairly accurate method for band structure calculation. Result provides fundamental insights in understanding the differences between the methodsof calculation and the corresponding modifications in the photonic bandgaps found in the band structure. Knowledge of such analysis helps to effectively tailor the bandgap structure in photonic crystals.
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Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific energy values... more
Transmission coefficient of a double quantum well device in presence of infinitely thick contact barriers considering GaAs/AlxGa1-xAs material composition provides the idea about probability of resonant tunneling at specific energy values less than barrier potential. Effects of different barrier width and well width on transmission coefficient are studied independently, and also for a specified structure, mole fraction for contact and middle barriers are independently varied to study transmission properties using transfer matrix technique. This also leads to the concept of variable effective mass which is incorporated in the solution of Schrödinger's equation, and comparative analysis is carried out for constant and variable effective mass in order to make the computation more realistic. Asymmetric potential effect on transmission coefficient is also observed by virtue of that consideration.
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Numerical computation of p+nn+ SDR IMPATT structure is carrier out at X-band and Ka-band by double iterative method involving simultaneous solution of Poisson's equation, continuity equation and space-charge equation subject to... more
Numerical computation of p+nn+ SDR IMPATT structure is carrier out at X-band and Ka-band by double iterative method involving simultaneous solution of Poisson's equation, continuity equation and space-charge equation subject to appropriate boundary conditions for electric field and normalized current density at depletion layer edges. Temperature-dependent two-step impact ionization process is considered for analysis purpose and carrier velocities are also
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