Nonlinear time-domain analysis of injection-locked microwave MESFET oscillators

In this paper, injection-locked MESFET oscillators are analyzed using several numerical models. The injection-locking behavior of the van der Pol equation and of a more complex representation using the Curtice-Cubic MESFET model are investigated. Analysis and experimental results are compared for an NE71083 transistor oscillator operating at 0.5 GHz. The deficiencies of using a van der Pol oscillator model are pointed out. Time-domain results from the complex model exhibiting multicycle and apparently chaotic behaviors are also examined, and point to problems with common nonlinear simulation techniques for these circuits.