An examination of recovery time of an integrated limiter/LNA

GaAs monolithic microwave integrated circuits (MMICs) are widely used in commercial and military microwave systems. Due to the fine geometry used in MMIC transistors, these circuits are susceptible to damage from high-power spurious electromagnetic (EM) radiation, either from microwave transmitters or nuclear electromagnetic pulse. Especially, low noise amplifiers (LNAs) in the front-end of microwave systems need high power protection because these amplifiers can sustain only low input power levels in the range of 10-20 dBm continuous wave (CW). To protect these circuits and maintain low noise figure, a high power and low loss limiter is required. The purpose of this application note is to document the test methodology employed and test results achieved measuring the small-signal gain recovery time of a balanced LNA with an integrated Schottky diode limiter and high power load.