Design considerations of high-efficiency GaAs IMPATT diodes

The efficiency and noise of p⁺n1n2n⁺GaAs IMPATT diodes have been studied as functions of the doping ratio n1/n2(when n1=n2we have a conventional abrupt p-n junction). For n1/n2>1 there are tradeoffs between efficiency and noise. At 12 GHz, for example, with a ratio of 4 the efficiency is 25 percent and the noise measure is 3 dB higher then that of a conventional IMPATT diode.