2–4 GHz wideband power amplifier with ultra‐flat gain and high PAE

Abstract

Demonstrated is a 2–4 GHz wideband power amplifier (WPA) using Cree 10 W GaN HEMT CGH40010. Also a novel process to find the optimum impedances is presented, with which the gain flatness can be taken into account. A compact PCB has been fabricated and tested with continuous waves at low (20 dBm) and high (28 dBm) input power level. From the measured results, at low power level, the gain is 13.1–14.1 dB across 2.0–3.9 GHz and 12.3–14.1 dB across 2.0–4.0 GHz. For large signals, power gain is 11.1–12.6 dB with power-added efficiency (PAE) 36.5–53.4% while output power is around 40 dBm. Gain flatness keeps less than 1 dB beyond 95% of the band. For a 5 MHz WCDMA signal, the adjacent channel leakage ratio of the WPA with digital predistortion reaches − 45.3 dBc with an average drain efficiency of 46.7%.