Nonlinear properties of GaAs Gunn diodes in the short-wave part of the millimeter-wave range

The volt-ampere characteristics and the ampere-watt sensitivity of GaAs Gunn diodes in the short-wave part of the millimeter-wave range were investigated. It is shown that at voltages of 2-2.5 V, significantly exceeding the threshold of statistical negative differential resistance, oscillations at frequencies of 70-75 GHz were observed, which were considerably higher than the expected transit-time frequency (approximately 40 GHz). The ampere-watt sensitivity of the Gunn diodes as measured in this study for a signal power of 10 mW is close to the best reported sensitivity value for Schottky-barrier diodes, and for signal power less than 0.1 mW the Gunn-diode sensitivity is significantly better than the Schottky-diode sensitivity. The high sensitivity of the Gunn diodes is maintained at a frequency of 150 GHz (0.6 A/W at a signal power of 1 mW).