A small signal analysis of an impatt device having two avalanche layers interspaced by a drift layer

Abstract

A small signal analysis of an IMPATT device (p-n-i-p-n structure) having two avalanche layers interspaced by a drift layer is carried out. When the widths of the two avalanche layers are different the device exhibits discrete negative conductance frequency bands separated by positive conductance frequency bands. Oscillations are expected to occur more favourably in the lowest frequency band where the maximum and minimum values of magnitudes of negative conductance and negative Q occur, respectively. When the two avalanche layer widths are equal, the device impedance is a high Q-reactance whose magnitude depends on the d.c. current. © 1974.