PERFORMANCE STUDY OF SERIES CONNECTED GUNN DIODES FOR MICROWAVE POWER GENERATION

Abstract

This dissertation addresses the theoretical concepts of series operation of. Gunn devices which lays the foundation of evaluating the performance of a series mutiple device oscillator. The performance is characterised by its power output and power combining efficiency. The objective is achieved by first realising an equivalent circuit for series operation and utilising it to carry out the performance study of series operation applicable to the entire gamut of the negative-resistance device family. It is found that the power output decreases with increasing r.f voltage and increases for increaase in bias voltage. The effects of increasing the number of active devices and the influenceof circuit and device parameters on the various aspects of the performance of series oscillator is studied. A trade off between power output and combining efficiency vis-a-vis number of devices is found to exist. The optimum negative conductance of an individual device plays an important role in determining the power combining efficiency. The performance of series connected Gunn diode power combining is studied as a particular case . using the circuit concept developed. A programme for calculation of optimum operating condition is developed and used for this purpose.