Progress with high efficiency IMPATT diodes

Abstract

High-efficiency diodes of early design were relatively noisy, wi th noise measures in excess of 50 dB. Recent designs have achieved noise measures about 10 dB lower. Unlike the uniformly-doped IMPATT diodes, the noise measure a t low R F levels does not improve very much, and hence, the high-efficiency diode may not be suitable for an application where the noise performance is critical. This has resulted in amplifier designs where flat-profile diodes are used for the first stages and high-efficiency diodes are used for the power stages.