Design of a Ka-band monolithic low noise amplifier

A Ka-band monolithic low noise amplifier (LNA) has been designed using a 0.1-μm gate length InGaAs pseudomorphic high electron-mobility transistor (pHEMT) process. The source inductors are adjusted to achieve best tradeoff among gain, return loss and noise figure. And the matching network is also carefully designed to get a compact chip size (1.4mm×0.75mm) besides keeping the circuit stable in lower frequency band than operating band. The simulated results of this chip show a gain of more than 13.1dB, a noise figure of less than 2.35dB, an input return loss of greater than 18dB, and an output return loss of greater than 18dB in the frequency range of 32.5 to 36.5GHz.