Amplifier Input Matching for NF-Gain-Linearity Compromise

In this paper we investigate the effect of amplifier input matching on the noise figure, gain, and linearity design tradeoff, with the goal of developing a single-amplifier solution able to operate as either a PA or LNA. We evaluate the large-signal linearity performance of an amplifier with a noise-matched input compared to an identical amplifier with gain-matched input, and the effects on efficiency and noise figure. The prototype amplifier is designed at 3 GHz and realizes 42.86 dBm CW output power and 67% PAE at 3 dB gain compression. With a noise-matched input the amplifier realizes a 2 dB reduction in gain and 7.7 percentage point reduction in PAE compared to the gain-matched amplifier, but a 3 dB improvement in IMD3 at 33.5 dBm output power under a 1-MHz spaced two-tone signal excitation.