Investigation of Some Guiding Structures for Low-Noise FET Amplifiers

The characteristics of low-noise amplifiers using various guiding structures have been investigated. A 0.15-0.20 dB improvement over the conventional microstrip amplifiers has been achieved at 48Hz with coplanar structures. Minimum noise temperatures of 45K and 10-12 K have been obtained at room and Iiquid nitrogen temperatures respectively. A two stage amplifier was realized at 198Hz exhtbiting a gain of 13-14 dB and 3 dB noise at room temperatures.