Power-Frequency Characteristics of the TRAPATT Diode Mode of High Efficiency Power Generation in Germanium and Silicon Avalanche Diodes

Abstract

We calculate in this paper the output power obtainable, versus frequency, for TRAPATT diodes. This high efficiency mode of operation is analyzed by means of a simplified model for both germanium and silicon avalanche diodes. The model evolved from a study of detailed computer simulations of experimental diode-circuit systems. The simplified analysis assumes: (i) The avalanche zone transit, plus the recovery time to the swept-out state, occurs in a half period of the TRAPATT frequency. (ii) The ratio of IMPATT frequency to TRAPATT frequency is 3:1. (iii) The diode area is chosen to provide 10 ohms negative resistance, a reasonable value for microwave circuits. The calculated electrical characteristics agree well with experimental observations. Consideration of circuit and thermal limitations results in a design for maximum power output for a millimeter wave silicon oscillator. Power output in excess of 1 watt CW, with an efficiency of 40 percent, is predicted at a frequency of 50 GHz.