A temperature‐compensated linear GaAs HBT power amplifier for small‐cell applications in −25 to 125∘C$^\circ \rm C$ lunar environment

A two-stage 920–960 MHz power amplifier (PA) in GaAs heterojunction bipolar transistor (HBT) process is demonstrated for small-cell communications in the lunar environment. To cope with the temperature fluctuations during lunar days, a novel complementary to absolute temperature (CTAT) biasing scheme is proposed for the PA to achieve an ultra-wide-range temperature compensation. Moreover, to meet the linearity requirements of the small-cell applications while producing high output power, a band-stop filter is employed in the biasing circuit of the second stage to reduce the AM– AM distortions. Over the temperature range of −25 to 125°C, the PA is capable of operating for the small-cell applications over a gain ranging from 30.2 to 32.8 dB. The proposed PA achieves 24.5 dBm linear power with −47 dBc adjacent channel leakage ratio (ACLR) and a PAE of 15%.