IMPATT pump sideband noise and its effect on parametric amplifier noise temperature

The amplitude modulation sideband noise of 38-GHz silicon IMPATT oscillators is investigated along with the effect of noise sidebands on the excess noise temperature of parametric amplifiers. It is shown that noise temperature may be affected under both large- and small-signal conditions to an extent that depends on the level of pump sideband noise. Simple expressions relating amplifier characteristics to pump noise power are presented for predicting the behavior of any amplifier with any pump. A pump-line bandpass filter is shown to reduce sideband noise to a level which allows an IMPATT pump to be used even in stringent satellite communication applications.