Using Nonlinear Dynamics Techniques to Analyze Microwave Oscillators

Partially because oscilloscope technology is far too slow to capture behavior in microwave frequency ranges, most microwave circuits analysis and modeling methods use frequency-domain representations. However, the frequency domain is only appropriate if the system under study is linear; linear systems have unique frequency-domain signatures, but two very different nonlinear systems can have indistinguishable spectra.

This project is a first stab at using nonlinear time-domain models and techniques to study a microwave circuit - in this case, an oscillator constructed out of a field-effect transistor (MESFET). The ultimate goal is to use this knowledge in order to design a composite oscillator composed of planar grid of MESFETs, and the idea is to exploit their nonlinear inter-device resonances in order to amplify the available power from the grid.

People:

This began as Jon Dixon's final project in CSCI 6446, and it later grew into his Ph.D. thesis in Electrical Engineering.
Zoya Popovic, Professor of Electrical and Computer Engineering, was Jon's primary supervisor.

Papers:

J. Dixon, E. Bradley, and Z. Popovic, "Nonlinear time-domain analysis of injection-locked microwave MESFET oscillators," IEEE Trans. on Microwave Theory and Technique, 45:1050-1057 (1997).