12 GHz Variable-Gain Amplifier with Dual-Gate GaAs FET for Satellite Use

Abstract

The performance of a single-stage variable-gain amplifier at 12 GHz is described, including intermodulation behaviour. The amplifier has a gain control range of 26 dB and a gain flatness of ± 0.5 dB over the 800 MHz bandwidth. Some fundamental features of the dual-gate FET such as noise, phase, and temperature behaviour are shown. The effect of second gate termination is studied by computer simulation, based on three-port s-parameters which have been measured up to 18 GHz.