D-band and G-band high-performance GaN power amplifier MMICs

In this article, we present a set of gallium nitride (GaN) power amplifiers (PAs) that provide state-of-the-art performance within the D-band (110-170 GHz) and G-band (140-220 GHz) frequencies. A four-stage cascode PA operates with more than 25 dB of small-signal gain over a 107-148-GHz band. At 120 GHz, it can deliver up to 26.4 dBm of output power and up to 16.5% of power-added efficiency (PAE) with more than 26 dB of gain at saturation. The combination of these parameters is among the best reported with a solid-state technology at such high frequencies. The two G-band circuits are able to provide up to 40 GHz of 3-dB bandwidth and gain exceeding 10 dB up to 190 GHz. The measured peak output power is 15.8 dBm at 181 GHz in 0.6-dB gain compression with a corresponding PAE of 2.4%. To the best of our knowledge, these amplifiers show the highest gain above 170 GHz and the highest output power above 150 GHz among any reported GaN-based MMICs.