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

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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.