2016 8th International Symposium on Telecommunications (IST), 2016
An ultra-wideband (UWB) low noise amplifier (LNA) with low power is presented in this paper. The ... more An ultra-wideband (UWB) low noise amplifier (LNA) with low power is presented in this paper. The proposed circuit is common gate and cascode topology that the power consumption, input and output impedance matching are optimized. Simulation results show that maximum gain and noise figure are 22.1dB and 2.4–2.9dB over a 3.1–10.6 GHz, respectively. Power consumption of the LNA core, buffer power and IIP3 are 7.7mW, 1.3 mW with 1.8 V supply and −9dBm respectively. The wideband input impedance matching of LNA is obtained by employing a degenerating inductor (|S11|<−7.5 dB). The circuit proposed UWB LNA is implemented using 0.18 µm based CMOS technology under TSMC.
In this paper, a new dual-band impedance matching circuit is presented by using a two-section mic... more In this paper, a new dual-band impedance matching circuit is presented by using a two-section microstrip transmission line and an open-circuit T-shape shunt stub. The governing analytical relations of the structure is first obtained based on transmission lines theory. Then, by applying the matching conditions on the obtained relations, i.e. matching an arbitrary load impedance with source impedance of 50Ω at desired frequencies, nonlinear equations are generated, and solved simultaneously, meeting the electrical and physical specifications of all parts of the scheme. In order to evaluate the performance of the proposed circuit, the scheme is depicted and simulated using HFSS software. Simulation results show that the relative bandwidth of the first and the second band are 76% and 11.8%, respectively. In comparison to the previously- schemes in literature, our proposed circuit yields to a wider bandwidth and less occupied area.
2014 Third Conference on Millimeter-Wave and Terahertz Technologies (MMWATT), 2014
This paper presents a new wideband fixed phase shifter with substrate integrated waveguide. Inser... more This paper presents a new wideband fixed phase shifter with substrate integrated waveguide. Inserting Air holes as a delay to create phase shift was presented before. But this paper applies from a new technique to insert the best count of Air holes and the best place of inserting Air holes. There is a direct relation between the counts of Air holes and the amount of phase shift. Two bits of phase shifts namely 15° and 30° are presented with the results of their simulation. They have 0.5° of phase ripple and their return losses and insertion losses are acceptable. These phase shifters could achieve 20% of bandwidth in KA frequency band from 32-40 GHz.
International Journal of RF and Microwave Computer-Aided Engineering
A new multiband circular polarized rectenna is implemented as a radio frequency (RF) power harves... more A new multiband circular polarized rectenna is implemented as a radio frequency (RF) power harvesting system tuned for the quad bands of 1.8 GHz (GSM 1800), 2.4/5.8 GHz (WLAN), and 3.6 GHz (WiMAX). An innovative monopole antenna is made for the rectenna; consisting of an octagonal shaped microstrip patch, loaded with an I‐shaped rectangular slot and three L‐shaped stubs so that the antenna creates circular polarization at the quad bands. The second part of the rectenna is a multi‐frequency impedance matching network (IMN) set between the antenna and the rectifier circuit. The IMN includes some parallel shunt stepped impedance stubs (SIS), which provides eight‐band matching network and connected to the rectifier, functioning at the frequencies of 0.84, 1.29, 1.68, 3.08, 3.45, 4.31, 5.11, and 5.49 GHz. Simulation and experimental results verify that the system operates well and deliver proper DC power. For input power of 0 dBm, the peak RF‐to‐DC power conversion efficiencies are 62.69%, 63.28%, 46.94%, 30.23%, 45.69%, 16.42%, 8.13%, and 19.61% at the eight frequency bands, which is higher than the recently reported rectennas.
An RF energy harvester (rectenna) consists of a broadband monopole antenna and a quad-band rectif... more An RF energy harvester (rectenna) consists of a broadband monopole antenna and a quad-band rectifying circuit is designed to harvest EM wave energy in the frequency range of 1.412 GHz to 8.56 GHz, which covers GSM-1800, LTE-band, Wimax, Wi-Fi, and WLAN. The initial component of the rectenna is an antenna that includes a semi-circular radiating patch with 8 circular stubs and a semicircle ground plane. The simulation results show the antenna has −10 dB impedance bandwidth at 7.148 GHz (from 1.412 GHz to 8.56 GHz). The second part of the rectenna is a rectifier circuit with a quad-band matching network for RF to DC conversion. The rectifier benefits from a two-stage Dickson rectifier using Schottky diodes. The RF-DC conversion efficiency and output DC voltage are simulated, and the maximum output voltage of the rectifier with the optimum load resistance of R=12 kΩ is 7.2 V, and the peak conversion efficiency is 65.3% when the input power to the rectifier is -4 dBm at 1.71 GHz.
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
AEU - International Journal of Electronics and Communications
This work introduces a method of pulse compression based on a higher-order soliton effect in a le... more This work introduces a method of pulse compression based on a higher-order soliton effect in a left-handed nonlinear (LH-NL) transmission line with series nonlinear capacitances. A circuit simulation of the LH-NL transmission line which is based on a finite-difference method shows that if a higher-order soliton is replaced by a fundamental soliton launched into the line, the self-phase modulation (SPM) will dominate the group velocity dispersion (GVD). As a result, the pulse compression is realized in a specific length dependent on the soliton order.
Straight long slots have high side-lobes in the far-field amplitude patterns, which reduces their... more Straight long slots have high side-lobes in the far-field amplitude patterns, which reduces their use as high-performance antennas. To reduce these side-lobes, a long slot may be tapered to produce the desired radiation patterns. The theory of control of the aperture distribution to reduce side-lobes has been already reported in some works and well known for already some decades. It is, however, shown in this paper that it may not be good enough to achieve ultra-low side lobes. The theory to analyze and design tapered leaky-wave antennas is described in this paper. Since it is very challenging to achieve a mathematical equation in this regard, some parameters will be calculated using simulation in the first step and the shape of the antenna field is obtained based on these parameters. In the next step, a differential equation is derived for the first step parameters. The solution of this differential equation which is the main motivation of this paper will be expressed in three ways...
The 8th European Conference on Antennas and Propagation (EuCAP 2014), 2014
A novel compact Frequency Reconfigurable Antenna (FRA) is presented for wireless network purposes... more A novel compact Frequency Reconfigurable Antenna (FRA) is presented for wireless network purposes. Using four p-i-n diodes employed across a moderately wide slot etched in a 32×35 mm2 ground plane, two measured independent (each one at one time) ultra-wide bandwidths (3.48-5.5 GHz and 5.18-7.35 GHz with S11<;-10 dB) are achieved for the first time with a measured 300 MHz bandwidth of overlap (%15 of ultra-wide bandwidths). Moreover, by appropriate switching six dualband modes with independent control of each band can be provided. Independent variation ranges are from 2.63 to 3 GHz for f1 and from 4.9 to 5.5 GHz for f2.
2014 Fourth International Conference on Advanced Computing & Communication Technologies, 2014
ABSTRACT This paper presents a triple band Microstrip slot antenna with SRR shape ring. The proto... more ABSTRACT This paper presents a triple band Microstrip slot antenna with SRR shape ring. The prototype antenna is designed and fabricated for wireless communication like IEEE 802.11(g/b/a), WIMAX and GPRS application. The bandwidths are around 5.1% for 1.93GHz (1880-1980), 35.4 % for 2.75 GHz (2400-3100 MHz) and 28% for 5.7GHz (4900-6500MHz).
Applied Computational Electromagnetics Society Journal
In this paper, a cruciform coupler with half mode substrate integrated waveguide (HMSIW) structur... more In this paper, a cruciform coupler with half mode substrate integrated waveguide (HMSIW) structure is presented. The prototype coupler consists of four half mode SIW structures which are crossing each other at right angles. Also, two metallic posts are inserted in free section of junction in order to make coupling properties. Compact size and broadband operation are the features of this coupler. The size of coupler is reduced by 24% in comparison to previous HMSIW cruciform couplers. A fractional bandwidth of about 35 % is obtained. The coupler is designed and simulated by HFSS13. Here, the simulation results are compared with experimental results
2008 International Symposium on Telecommunications, 2008
... 53, No. 3, pp. 9941003, March 2005. [7] F.Geran, G. Dadashzadeh, M. Fardis, N. Hojjat, A.Ahm... more ... 53, No. 3, pp. 9941003, March 2005. [7] F.Geran, G. Dadashzadeh, M. Fardis, N. Hojjat, A.Ahmadi, "Rectangular Slot with a Novel Triangular Ring Microstrip Fed for UWB Applications," Journal of Electromagnetic Waves and Applications, Vol.21, pp. 387-396, 2007. ...
2016 8th International Symposium on Telecommunications (IST), 2016
An ultra-wideband (UWB) low noise amplifier (LNA) with low power is presented in this paper. The ... more An ultra-wideband (UWB) low noise amplifier (LNA) with low power is presented in this paper. The proposed circuit is common gate and cascode topology that the power consumption, input and output impedance matching are optimized. Simulation results show that maximum gain and noise figure are 22.1dB and 2.4–2.9dB over a 3.1–10.6 GHz, respectively. Power consumption of the LNA core, buffer power and IIP3 are 7.7mW, 1.3 mW with 1.8 V supply and −9dBm respectively. The wideband input impedance matching of LNA is obtained by employing a degenerating inductor (|S11|<−7.5 dB). The circuit proposed UWB LNA is implemented using 0.18 µm based CMOS technology under TSMC.
In this paper, a new dual-band impedance matching circuit is presented by using a two-section mic... more In this paper, a new dual-band impedance matching circuit is presented by using a two-section microstrip transmission line and an open-circuit T-shape shunt stub. The governing analytical relations of the structure is first obtained based on transmission lines theory. Then, by applying the matching conditions on the obtained relations, i.e. matching an arbitrary load impedance with source impedance of 50Ω at desired frequencies, nonlinear equations are generated, and solved simultaneously, meeting the electrical and physical specifications of all parts of the scheme. In order to evaluate the performance of the proposed circuit, the scheme is depicted and simulated using HFSS software. Simulation results show that the relative bandwidth of the first and the second band are 76% and 11.8%, respectively. In comparison to the previously- schemes in literature, our proposed circuit yields to a wider bandwidth and less occupied area.
2014 Third Conference on Millimeter-Wave and Terahertz Technologies (MMWATT), 2014
This paper presents a new wideband fixed phase shifter with substrate integrated waveguide. Inser... more This paper presents a new wideband fixed phase shifter with substrate integrated waveguide. Inserting Air holes as a delay to create phase shift was presented before. But this paper applies from a new technique to insert the best count of Air holes and the best place of inserting Air holes. There is a direct relation between the counts of Air holes and the amount of phase shift. Two bits of phase shifts namely 15° and 30° are presented with the results of their simulation. They have 0.5° of phase ripple and their return losses and insertion losses are acceptable. These phase shifters could achieve 20% of bandwidth in KA frequency band from 32-40 GHz.
International Journal of RF and Microwave Computer-Aided Engineering
A new multiband circular polarized rectenna is implemented as a radio frequency (RF) power harves... more A new multiband circular polarized rectenna is implemented as a radio frequency (RF) power harvesting system tuned for the quad bands of 1.8 GHz (GSM 1800), 2.4/5.8 GHz (WLAN), and 3.6 GHz (WiMAX). An innovative monopole antenna is made for the rectenna; consisting of an octagonal shaped microstrip patch, loaded with an I‐shaped rectangular slot and three L‐shaped stubs so that the antenna creates circular polarization at the quad bands. The second part of the rectenna is a multi‐frequency impedance matching network (IMN) set between the antenna and the rectifier circuit. The IMN includes some parallel shunt stepped impedance stubs (SIS), which provides eight‐band matching network and connected to the rectifier, functioning at the frequencies of 0.84, 1.29, 1.68, 3.08, 3.45, 4.31, 5.11, and 5.49 GHz. Simulation and experimental results verify that the system operates well and deliver proper DC power. For input power of 0 dBm, the peak RF‐to‐DC power conversion efficiencies are 62.69%, 63.28%, 46.94%, 30.23%, 45.69%, 16.42%, 8.13%, and 19.61% at the eight frequency bands, which is higher than the recently reported rectennas.
An RF energy harvester (rectenna) consists of a broadband monopole antenna and a quad-band rectif... more An RF energy harvester (rectenna) consists of a broadband monopole antenna and a quad-band rectifying circuit is designed to harvest EM wave energy in the frequency range of 1.412 GHz to 8.56 GHz, which covers GSM-1800, LTE-band, Wimax, Wi-Fi, and WLAN. The initial component of the rectenna is an antenna that includes a semi-circular radiating patch with 8 circular stubs and a semicircle ground plane. The simulation results show the antenna has −10 dB impedance bandwidth at 7.148 GHz (from 1.412 GHz to 8.56 GHz). The second part of the rectenna is a rectifier circuit with a quad-band matching network for RF to DC conversion. The rectifier benefits from a two-stage Dickson rectifier using Schottky diodes. The RF-DC conversion efficiency and output DC voltage are simulated, and the maximum output voltage of the rectifier with the optimum load resistance of R=12 kΩ is 7.2 V, and the peak conversion efficiency is 65.3% when the input power to the rectifier is -4 dBm at 1.71 GHz.
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
AEU - International Journal of Electronics and Communications
This work introduces a method of pulse compression based on a higher-order soliton effect in a le... more This work introduces a method of pulse compression based on a higher-order soliton effect in a left-handed nonlinear (LH-NL) transmission line with series nonlinear capacitances. A circuit simulation of the LH-NL transmission line which is based on a finite-difference method shows that if a higher-order soliton is replaced by a fundamental soliton launched into the line, the self-phase modulation (SPM) will dominate the group velocity dispersion (GVD). As a result, the pulse compression is realized in a specific length dependent on the soliton order.
Straight long slots have high side-lobes in the far-field amplitude patterns, which reduces their... more Straight long slots have high side-lobes in the far-field amplitude patterns, which reduces their use as high-performance antennas. To reduce these side-lobes, a long slot may be tapered to produce the desired radiation patterns. The theory of control of the aperture distribution to reduce side-lobes has been already reported in some works and well known for already some decades. It is, however, shown in this paper that it may not be good enough to achieve ultra-low side lobes. The theory to analyze and design tapered leaky-wave antennas is described in this paper. Since it is very challenging to achieve a mathematical equation in this regard, some parameters will be calculated using simulation in the first step and the shape of the antenna field is obtained based on these parameters. In the next step, a differential equation is derived for the first step parameters. The solution of this differential equation which is the main motivation of this paper will be expressed in three ways...
The 8th European Conference on Antennas and Propagation (EuCAP 2014), 2014
A novel compact Frequency Reconfigurable Antenna (FRA) is presented for wireless network purposes... more A novel compact Frequency Reconfigurable Antenna (FRA) is presented for wireless network purposes. Using four p-i-n diodes employed across a moderately wide slot etched in a 32×35 mm2 ground plane, two measured independent (each one at one time) ultra-wide bandwidths (3.48-5.5 GHz and 5.18-7.35 GHz with S11<;-10 dB) are achieved for the first time with a measured 300 MHz bandwidth of overlap (%15 of ultra-wide bandwidths). Moreover, by appropriate switching six dualband modes with independent control of each band can be provided. Independent variation ranges are from 2.63 to 3 GHz for f1 and from 4.9 to 5.5 GHz for f2.
2014 Fourth International Conference on Advanced Computing & Communication Technologies, 2014
ABSTRACT This paper presents a triple band Microstrip slot antenna with SRR shape ring. The proto... more ABSTRACT This paper presents a triple band Microstrip slot antenna with SRR shape ring. The prototype antenna is designed and fabricated for wireless communication like IEEE 802.11(g/b/a), WIMAX and GPRS application. The bandwidths are around 5.1% for 1.93GHz (1880-1980), 35.4 % for 2.75 GHz (2400-3100 MHz) and 28% for 5.7GHz (4900-6500MHz).
Applied Computational Electromagnetics Society Journal
In this paper, a cruciform coupler with half mode substrate integrated waveguide (HMSIW) structur... more In this paper, a cruciform coupler with half mode substrate integrated waveguide (HMSIW) structure is presented. The prototype coupler consists of four half mode SIW structures which are crossing each other at right angles. Also, two metallic posts are inserted in free section of junction in order to make coupling properties. Compact size and broadband operation are the features of this coupler. The size of coupler is reduced by 24% in comparison to previous HMSIW cruciform couplers. A fractional bandwidth of about 35 % is obtained. The coupler is designed and simulated by HFSS13. Here, the simulation results are compared with experimental results
2008 International Symposium on Telecommunications, 2008
... 53, No. 3, pp. 9941003, March 2005. [7] F.Geran, G. Dadashzadeh, M. Fardis, N. Hojjat, A.Ahm... more ... 53, No. 3, pp. 9941003, March 2005. [7] F.Geran, G. Dadashzadeh, M. Fardis, N. Hojjat, A.Ahmadi, "Rectangular Slot with a Novel Triangular Ring Microstrip Fed for UWB Applications," Journal of Electromagnetic Waves and Applications, Vol.21, pp. 387-396, 2007. ...
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Papers by Fatemeh Geran