A simplified approach to predicting negative resistance in a microwave transistor with series feedback

This paper addresses the question of how to predict the series feedback termination required to generate negative resistance in a microwave transistor in different circuit configurations. Although this question is usually approached through computer modelling and simulation, we present here a simple...

Full description

Saved in:
Bibliographic Details
Published in2013 IEEE MTT-S International Microwave Symposium Digest (MTT) pp. 1 - 4
Main Authors Poole, C. R., Darwazeh, I. Z.
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.06.2013
Subjects
Mathematical model
Microwave circuits
Microwave oscillators
Microwave transistors
Resistance
Scattering parameters
Transistors
Online AccessGet full text

Cover

More Information
Summary:This paper addresses the question of how to predict the series feedback termination required to generate negative resistance in a microwave transistor in different circuit configurations. Although this question is usually approached through computer modelling and simulation, we present here a simple closed form equation that predicts the value of feedback reactance most likely to generate negative resistance at the input of a 2-port sub-circuit comprising a transistor plus series feedback, based solely on the 2-port S-parameters of the transistor. This simple equation provides new insight into the effect of series feedback on a transistor and leads us to propose a general rule, namely that the series feedback reactance required to generate negative resistance in a given transistor in a given configuration depends on the sign of the imaginary part of the sum of the 2-port S-parameters for the device in that configuration.
ISSN:0149-645X
2576-7216
DOI:10.1109/MWSYM.2013.6697356