Utilization of nonlinear properties of IMPATT-diodes in microwave devices (survey)

Applications for IMPATT diodes with utilization of their nonlinear properties in microwave devices are reviewed from the standpoint of design and performance. The three major applications are harmonic oscillators, frequency multipliers and frequency converters. Power and frequency ratings of those devices using IMPATT diodes as well as particular characteristics such as conversion efficiency, bandwidth, i-f power and dc power, based on Soviet and foreign manufacturers' data, are compared with those of corresponding devices on Gunn-effect or Schottky-barrier diodes. The survey indicates that microwave devices with IMPATT diodes have the highest efficiency, source devices being the principal available power sources at frequencies above 200 GHz, and that a waveguide construction of microwave devices is the preferable one. The performance of harmonic oscillators with IMPATT diodes can be optimized by selecting the electron transit frequency equal to the output harmonic frequency and adding a tunable idle fundamental frequency resonator, the stability of harmonic oscillations being raised by synchronization of the fundamental frequency oscillations. Frequency multiplication requires high-power low-noise IMPATT diodes with high stability, as a replacement for varactors, with a nonresonant capacitive load for ensuring high conversion efficiency.