An Unusual Microwave Mixer

Some preliminary measurements on an unusual microwave mixer configuration are reported. The mixer employied a single gate, packaged GaAs FET in a novel coaxial mount. The L.O. power and the I.F. were fed to and taken from the drain while the input R.F. signal was connected to the gate. A conversion gain of 2 dB and 270K DSB "mixer" noise temperature were measured at X band. Cooling the unit to 60K, a "mixer" noise temperature of 80K was obtained across a 10% bandwidth. At K band a 3 dB conversion loss and 880K DSB noise temperature were measured. The latter figure dropped to l80K at cryogenic temperatures.