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Non-foster antenna matching networks using reflection-mode negative-group-delay networks

Almahroug, Alhasan Ali Mosftah (2018)
Ph.D. thesis, University of Birmingham.

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Non-Foster networks provide a possible route for broad band matching of antennas. The major challenges when
designing non-Foster elements using conventional Negative Impedance Converters (NICs) arise from the stability concerns, due to the existence of the feedback in the circuitry and the generation of negative impedance. Therefore, investigation of alternative means for designing non-Foster elements which are more stable is imperative. This thesis presents a new perspective in designing non-Foster reactive elements based on negative group delay (NGD) networks. A novel reflection-mode NGD network is designed, fabricated and tested. Subsequently, a novel approach which contains a negative resistance amplifier and a Lange coupler is introduced to compensate the losses of the NGD networks. A simple equivalent circuit model (-L, -C) of the proposed NGD-based non-Foster network is presented and can be used to deploy the non-Foster network in an antenna matching network. Theoretical analysis based on Nyquist approach shows that stability can be achieved but practical implementation issues can cause stability problems. . Finally, approximate calculations of the non-linearity and noise performance addressing the operational limitations of the proposed circuit in transmit and receive applications have been introduced.

Type of Work:Ph.D. thesis.
Supervisor(s):Gardner, Peter and Feresidis, Alexandros
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Engineering, Department of Electronic, Electrical and Systems Engineering
Additional Information:

A. A. Almahroug, A. P. Feresidis, and P. Gardner, "Non-Foster antenna
matching networks using reflection-mode negative-group-delay networks,"
in 2016 Loughborough Antennas & Propagation Conference (LAPC), 2016,
pp. 1-4.

Subjects:TA Engineering (General). Civil engineering (General)
TK Electrical engineering. Electronics Nuclear engineering
Institution:University of Birmingham
ID Code:8417
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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