IEEE Transactions on Antennas and Propagation, 2012
This work presents a novel dual-feed planar inverted-F antenna (PIFA) suitable for wireless appli... more This work presents a novel dual-feed planar inverted-F antenna (PIFA) suitable for wireless applications such as wireless local area network (WLAN) and long term evolution (LTE) as a diversity and multiple-input multiple-output (MIMO) antenna. Instead of two antenna elements, there is only one top radiating element with two isolated feeding ports which can save space and cost. The two feed plates are placed perpendicular to each other to exploit both the polarization diversity and pattern diversity. The isolation between the two antenna ports is achieved by modifying the ground plane under the top radiating element. Simulated and measured results are obtained to verify the conclusion .
Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles ... more Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles by inert gas condensation, incorporating in the 1-methyl-2-pyrrolidinone (NMP) solution of polyaniline emeraldine base (PANIEB) and then cast into films at 120 °C. X-ray diffraction confirmed the presence of ~67 nm silver nanoparticles in the polyaniline matrix. From the thermogravimetric analysis it is observed that the nanocomposite films have a higher degradation temperature than the pure PANI film. Scanning electron microscopy showed a uniform distribution, with spherical and granular morphology for low concentration of Ag nanoparticles, whereas for higher concentration (1.0% Ag) nanorods are formed. The impedance spectroscopic studies of NMP plasticized nanocomposite films suggest microphase separation into reduced and oxidized repeat units. Incorporation of silver nanoparticles in PANI reduces the charge trapping centres and increases the conducting channels, which causes a tenfold decrease in the real part of impedance.
Recently, Wheeler cap method was extended to measure wideband antennas. This paper presents an in... more Recently, Wheeler cap method was extended to measure wideband antennas. This paper presents an investigation on the effects of the loss of wheeler cap on antenna efficiency measurement results. Two caps/cavities (one large and one small) are employed for this study and numerical simulation is also conducted to aid the analysis. Both the experimental and numerical results show the loss due to the imperfection of the cavity can cause a serious problem for obtaining an accurate result. How to eliminate the effects of the cavity loss and improve the measurement accuracy for the wheeler extended method is an issue to be resolved.
An empirical expression for the base transit time, τb, of a bipolar transistor with exponential b... more An empirical expression for the base transit time, τb, of a bipolar transistor with exponential base doping profile is derived considering doping and field dependence of mobility. In the analysis, bandgap-narrowing effect, high injection effect and carrier velocity saturation at the base edge of the collector-base junction are also incorporated. The collector current density, Jc, and minority carrier stored charge,
Most portable UWB antennas generate near omni-directional radiation pattern which is not suitable... more Most portable UWB antennas generate near omni-directional radiation pattern which is not suitable for some applications. In this paper, we present a numerical and experimental investigation of a wideband (4.5 GHz to 8.5 GHz) microstrip slot antenna of reduced size which produces a directional pattern. It is found that the optimum design of this antenna can be achieved by cutting
Over the past 10 years or so, many broadband and ultra-wideband antennas have been developed for ... more Over the past 10 years or so, many broadband and ultra-wideband antennas have been developed for broadband high data rate mobile communications. It is realized how to make efficient and accurate measurements for such antennas could be a challenging issue. In this paper, we examine the antenna efficiency measurement techniques which have been used up to now, and identify their
Medical Information Bus (MIB) is a standard designed to allow different medical instrument manufa... more Medical Information Bus (MIB) is a standard designed to allow different medical instrument manufacturers to transmit data from their instruments to a host computer. The authors felt that such a system, if developed without any field experience and feedback from end users, might be impractical. Therefore, they developed and implemented an MIB system using IV pumps. The MIB standard at that time was used for the system development. After a few trials and design modifications based on the user feedback, a system was designed to collect data from IV pumps. The system includes device communication controllers as the pump-MIB interface and a master communication controller capable of communicating with up to 254 devices in one unit as the host interface. The MIB host system software on a Charles River Data Systems micromini and host system was modified to acquire data for HELP, the hospital information system.>
In this paper, we discuss the design and the development of a highly customizable interactive pla... more In this paper, we discuss the design and the development of a highly customizable interactive platform ‘Guess Who’, which was designed as a tool for investigating human emotions in a variety of experimental setups. In its essence, ‘Guess Who?’ is actually a game, which includes typical game elements (winning, loosing, scoring) and can also be played purely for entertainment purposes. The design of the game includes three major elements; 1) experimenter- friendly customizable interface, 2) single player mode-laying against an intelligent computer, 3) two player mode - playing with a remote opponent over the internet via audio video communication channel. Early user evaluations show that Guess Who game is not only a very productive research tool for researchers, where researchers are able to record valuable data in different experimental conditions in a natural way, but also a great source of entertainment for children.
IEEE Transactions on Antennas and Propagation, 2012
This work presents a novel dual-feed planar inverted-F antenna (PIFA) suitable for wireless appli... more This work presents a novel dual-feed planar inverted-F antenna (PIFA) suitable for wireless applications such as wireless local area network (WLAN) and long term evolution (LTE) as a diversity and multiple-input multiple-output (MIMO) antenna. Instead of two antenna elements, there is only one top radiating element with two isolated feeding ports which can save space and cost. The two feed plates are placed perpendicular to each other to exploit both the polarization diversity and pattern diversity. The isolation between the two antenna ports is achieved by modifying the ground plane under the top radiating element. Simulated and measured results are obtained to verify the conclusion .
Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles ... more Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles by inert gas condensation, incorporating in the 1-methyl-2-pyrrolidinone (NMP) solution of polyaniline emeraldine base (PANIEB) and then cast into films at 120 °C. X-ray diffraction confirmed the presence of ~67 nm silver nanoparticles in the polyaniline matrix. From the thermogravimetric analysis it is observed that the nanocomposite films have a higher degradation temperature than the pure PANI film. Scanning electron microscopy showed a uniform distribution, with spherical and granular morphology for low concentration of Ag nanoparticles, whereas for higher concentration (1.0% Ag) nanorods are formed. The impedance spectroscopic studies of NMP plasticized nanocomposite films suggest microphase separation into reduced and oxidized repeat units. Incorporation of silver nanoparticles in PANI reduces the charge trapping centres and increases the conducting channels, which causes a tenfold decrease in the real part of impedance.
Recently, Wheeler cap method was extended to measure wideband antennas. This paper presents an in... more Recently, Wheeler cap method was extended to measure wideband antennas. This paper presents an investigation on the effects of the loss of wheeler cap on antenna efficiency measurement results. Two caps/cavities (one large and one small) are employed for this study and numerical simulation is also conducted to aid the analysis. Both the experimental and numerical results show the loss due to the imperfection of the cavity can cause a serious problem for obtaining an accurate result. How to eliminate the effects of the cavity loss and improve the measurement accuracy for the wheeler extended method is an issue to be resolved.
An empirical expression for the base transit time, τb, of a bipolar transistor with exponential b... more An empirical expression for the base transit time, τb, of a bipolar transistor with exponential base doping profile is derived considering doping and field dependence of mobility. In the analysis, bandgap-narrowing effect, high injection effect and carrier velocity saturation at the base edge of the collector-base junction are also incorporated. The collector current density, Jc, and minority carrier stored charge,
Most portable UWB antennas generate near omni-directional radiation pattern which is not suitable... more Most portable UWB antennas generate near omni-directional radiation pattern which is not suitable for some applications. In this paper, we present a numerical and experimental investigation of a wideband (4.5 GHz to 8.5 GHz) microstrip slot antenna of reduced size which produces a directional pattern. It is found that the optimum design of this antenna can be achieved by cutting
Over the past 10 years or so, many broadband and ultra-wideband antennas have been developed for ... more Over the past 10 years or so, many broadband and ultra-wideband antennas have been developed for broadband high data rate mobile communications. It is realized how to make efficient and accurate measurements for such antennas could be a challenging issue. In this paper, we examine the antenna efficiency measurement techniques which have been used up to now, and identify their
Medical Information Bus (MIB) is a standard designed to allow different medical instrument manufa... more Medical Information Bus (MIB) is a standard designed to allow different medical instrument manufacturers to transmit data from their instruments to a host computer. The authors felt that such a system, if developed without any field experience and feedback from end users, might be impractical. Therefore, they developed and implemented an MIB system using IV pumps. The MIB standard at that time was used for the system development. After a few trials and design modifications based on the user feedback, a system was designed to collect data from IV pumps. The system includes device communication controllers as the pump-MIB interface and a master communication controller capable of communicating with up to 254 devices in one unit as the host interface. The MIB host system software on a Charles River Data Systems micromini and host system was modified to acquire data for HELP, the hospital information system.>
In this paper, we discuss the design and the development of a highly customizable interactive pla... more In this paper, we discuss the design and the development of a highly customizable interactive platform ‘Guess Who’, which was designed as a tool for investigating human emotions in a variety of experimental setups. In its essence, ‘Guess Who?’ is actually a game, which includes typical game elements (winning, loosing, scoring) and can also be played purely for entertainment purposes. The design of the game includes three major elements; 1) experimenter- friendly customizable interface, 2) single player mode-laying against an intelligent computer, 3) two player mode - playing with a remote opponent over the internet via audio video communication channel. Early user evaluations show that Guess Who game is not only a very productive research tool for researchers, where researchers are able to record valuable data in different experimental conditions in a natural way, but also a great source of entertainment for children.
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Papers by Hassan Tariq