High-efficiency GaAs transferred electron device operation and circuit design

In this paper it is shown that a GaAs transferred electron device is adequately described by a simple, static IV characteristic. This characteristic is used in a time domain computer simulation with the microwave circuit represented by transmission line equivalent circuit from which the voltage and current waveforms associated with the device are derived for a particular device IV characteristic and circuit. These data are analyzed for efficiency, frequency of oscillation, and starting transient and then are observed as various device and circuit parameters are changed in the simulation. From this study and parameter scan, the criterion for an efficient GaAs oscillator circuit and the maximum dc to RF conversion efficiency for device of a given quality, as specified by its current peak to valley ratio are found. Experimental observation of waveforms and efficiency and their dependence on the circuit and device parameters were then seen to be in good agreement, thus justifying the use of the phenomenological I-V characteristic. For a device with a current peak to valley ratio of 2, the theoretical and experimentally observed conversion efficiency limit appears to be slightly less than 20 percent. The use of the simple I- V characteristic is appropriate down to frequencies less than the "transit" frequency.