X-band monolithic four-stage LNA with pulse-doped GaAs MESFETs

An X-band monolithic four-stage low-noise amplifier (LNA) with 0.5- mu m-gate pulse-doped GaAs MESFETs has been demonstrated. At 12 GHZ this LNA has a noise figure of 1.67 dB, with 18.5-dB gain, an input VSWR of less than 1.6:1, and an output VSWR of less than 1.8:1. Noise figure, gain, and VSWRs show very little bias current dependence due to the exceptional features of the pulse-doped structure FETs and the optimized circuit design. Insensitivity to bias current implies performance stability in the face of process fluctuations. Thus, high yield is obtained, making this device suitable for mass production.<>