THE OPTIMUM WIDTH FOR LHL-GaAs-IMPATT DIODES

Abstract

In this paper the results of an extensive study of the effects of the drift region width on the performance of LHL-GaAs-IMPATT diodes are presented. These results have been obtained using an IMPATT-diode full scale computer simulation program. It is demonstrated that the transition between the regular IMPATT mode and the high-efficiency modes becomes more abrupt as the drift region width is increased. It is also found that when the diode operates according to the highefficiency modes the efficiency is not a sensitive function of the drift region width. The anomalous behaviour of the admittance of the diode is found to be caused by the increase of the component of the total current.contributing to the power generation mechanism at the expenense of the cold-capacitive current. It is demonstrated that for the diodes whose drift region width is optimized for the regular IMPATT mode the efficiency remains always high and the hysterises in the tuning characteristics are less significant

A PROPOSED METHOD FOR IMPROVING THE PERFORMANC OF P-TYPE InP IMPATT

“…Since these effects are inherent in InP material, it is only possible to improve the performance of p-type InP IMPATTs through modifying the microwave circuit where the diode is imbedded. Since it has been previously reported that the performance of IMPATTs could be improved if it is driven by a nonsinusoidal voltage waveform [4][5][6][7], the external circuit attached to the diode must be capable of supporting such waveforms. However, no comprehensive study has been conducted for determining the optimum waveform.…”

“…A special waveform is proposed to be the optimum waveform for p-type InP IMPATT. This proposition is supported by an extensive investigation of IMPATT operation [1][2][3][7][8]. This investigation has been conducted using a modified version of the full-scale computer simulation program described elsewhere [8].…”