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W-shaped enhanced-bandwidth patch antenna for wireless communication
, Article Wireless Personal Communications ; Volume 43, Issue 4 , May , 2007 , Pages 1257-1265 ; 09296212 (ISSN) ; Hojjat Kashani, F ; Barkeshli, K ; Sharif University of Technology
2007
Abstract
In this paper a novel form of the familiar E-shaped patch antenna is presented. In the presented approach, by using the genetic algorithm (GA) based on fuzzy decision-making, some modifications have been implemented to the incorporated slots which lead to even more enhancement in the antenna bandwidth. The MOM (Method of Moment) is employed for analysis at the frequency band of 1.8GHz-2.6GHz by the optimization parameters of supply locations and slot dimensions. In the implemented fuzzy system, inputs are parameters like population, and outputs are parameters like recombination to produce the next generation. Fuzzy inference system (FIS) is used for the control of GA parameters. The design...
Design and Implementation of Integrated Broadband Low-Noise Amplifier
, Ph.D. Dissertation Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Broadband low-noise amplifiers (LNAs) find widespread application in many communication and measurement systems, and extensive research efforts have been devoted to improve their performances. The main efforts include the system bandwidth enhancement for increasing the data rate, the system noise reduction for improving sensitivity of receivers, and lowering the power consumption for increasing battery life of handheld systems. There is a steady quest to develop novel circuit architectures and design methodologies that can pave the way for performance enhancement of overall system.In this thesis, the design and implementation of a broadband low-noise amplifier circuit is investigated. The...
Design and analysis of broadband darlington amplifiers with bandwidth enhancement in GaAs pHEMT technology
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 62, Issue 8 , August , 2014 , Pages 1705-1715 ; ISSN: 00189480 ; Medi, A ; Sharif University of Technology
Abstract
This paper presents a bandwidth enhancement technique for broadband Darlington amplifiers. A detailed analysis of the high-frequency performance of the Darlington amplifier and the effect of bandwidth enhancement is provided. A design procedure is also given for broadband feedback Darlington amplifiers with bandwidth enhancement and gain flattening. A single- and a three-stage feedback amplifier with the proposed improvements are designed and implemented in a 0.25-μm Al-GaAs-InGaAs pHEMT technology. The single-stage amplifier provides 6 ± 0.4 dB of small-signal gain in the frequency band of 1-30 GHz. The three-stage amplifier features 17.8 ± 0.8 dB of small-signal gain in the frequency band...
Transformer-feedback interstage bandwidth enhancement for MMIC multistage amplifiers
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 63, Issue 2 , 2015 , Pages 441-448 ; 00189480 (ISSN) ; Medi, A ; Sharif University of Technology
Abstract
The transformer-feedback (TRFB) interstage bandwidth enhancement technique for broadband multistage amplifiers is presented. Theory of the TRFB bandwidth enhancement and the design conditions for maximum bandwidth, maximally flat gain, and maximally flat group delay are provided. It is shown that the TRFB bandwidth enhancement can provide higher bandwidth compared to the conventional techniques based on reactive impedance matching networks. A three-stage low-noise amplifier (LNA) monolithic microwave integrated circuit with the TRFB between its consecutive stages is designed and implemented in a 0.1-μ m GaAs pHEMT process. The TRFB is realized by coupling between the drain bias lines of...
A broadband multistage LNA with bandwidth and linearity enhancement
, Article IEEE Microwave and Wireless Components Letters ; Volume PP, Issue 99 , 2016 ; 15311309 (ISSN) ; Yousefi, A ; Kalantari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Design techniques to enhance bandwidth and linearity of broadband multistage low-noise amplifiers (LNAs) are presented. A feedback amplifier circuit is proposed to compensate for transistor gain roll-off with frequency in other amplifier stages and extend overall bandwidth. Moreover, a transistor width tapering in a multistage LNA is applied to improve linearity. These techniques are adopted in a three-stage monolithic microwave integrated circuit (MMIC) LNA implemented in a 0.1-μm GaAs pHEMT process. The LNA features 18-43 GHz bandwidth, 21.6 dB average gain, and 1.8-2.7 noise figure (NF). It exhibits output 1-dB compression point of 11.5 dBm at 30 GHz and consumes 70 mA bias current from a...