A 52-58 GHz Power Amplifier with 18.6-dBm Saturated Output Power for Space Applications

This paper presents a 52-58 GHz power amplifier (PA) with constant output power across the entire band. A new topology based on the impedance transformation of transmission lines was adopted as the inter-stage matching network. Compared with the conventional 2-section LC matching topology, our approach reduced the matching loss by 1.5 dB at 54 GHz. Such topology made the design capable of operating at a frequency close to 80% of the unit-current-gain cut-off frequency (fT) specified by the device technology. Additionally, stacked-FET was adopted as the power stage for the output power enhancement in a broadband sense. Implemented in the commercially available 0.15-μm GaAs pseudomorphic high-electron-mobility transistor (pHEMT) process, the 2-stage PA demonstrated a small-signal gain of 14.7 dB, a saturated output power (Psat) of 18.6 dBm, and a maximum power-added-efficiency (PAE) of 18.2% at 54 GHz.