Approximate large-signal analysis of IMPATT oscillators

Insight into the large-signal operating characteristics of IMPATT oscillators has been obtained from detailed numerical calculations of D. L. Scharfetter and H. K. Gummel. However, their calculations are relatively expensive in computer time. Small-signal analyses of IMPATT diodes are much less expensive, but give little reliable information about oscillator performance. This paper presents a model for large-signal analysis of IMPATT diodes which requires less than 1 percent of the computer time used by Scharfetter and Gummel's method, but still provides a realistic description of IMPATT oscillators in modes of operation which maintain carrier velocity saturation. We show graphical results, based on numerical computations, which provide information about phase relationships in IMPATT oscillators and improve understanding of the two-frequency mode of operation.