Monolithic GaAs FET low-noise amplifiers for X-band applications

Monolithic microwave components fabricated on GaAs substrates afford an opportunity to meet and exceed hybrid microwave amplifier performance with greatly reduced cost, size, and weight. Advances in monolithic microwave integrated circuit (MMIC) technology have produced significant improvements in component accuracy and repeatability, permitting the circuit designer to design more complex circuits in less space with a greater degree of confidence. The design, fabrication, and performance of X-band monolithic noise amplifiers are described. Noise figures under 4 dB are shown to be possible with good input match and high gain using GaAs MMICs of either the balanced common-source amplifier approach or the common-gate input active matching approach. With minor process and circuit design improvements, noise figures of 3 dB are expected.