Gunn diodes with improved frequency-stability/temperature variations

Improved frequency-stability/temperature variations have been obtained for Gunn diodes by using n+ contacts. 20 mW diodes were operated in a low-Q factor invar coaxial cavity. On decoupling by 6 dB, a total frequency drift as little as 9 MHz over the temperature range ¿75°C to +60°C has been observed, i.e. less than 70 kHz/degC. This is compared to results of silver¿tin-contact devices showing the usual drift of about ¿1 MHz/degC. The absence of contact resistance in the n+ contact devices is the primary reason for their improved stability.