Performance of Some GaAs Mesfet Mixers

The performance of MESFET mixers used as down-converters from frequencies around 8 GHz to an intermediate frequency of 1 GHz is presented. Several possible mixer configurations have been considered and preliminary results are described involving the use of the MESFET in single as well as double device circuits. Experimental results concern the devices single sideband. noise figures and associated values of small signal conversion gain. Large signal saturation is discussed and results of third order intermodulation product are described. A single sideband noise figure of 7.8 dB associate with a gain of 8 dB at 7 GHz has been measured from a mixer using a single transistor.