A 240 W power heterojunction FET with high efficiency for W-CDMA base stations

An L/S-band highly efficient 240 W GaAs FET amplifier has been developed. The amplifier employed newly developed pseudomorphic heterojunction FETs (HJFETs) exhibiting large drain current and high gm characteristics. In addition, we employed the second harmonic tuning for the input and output matching circuit to obtain the high efficiency characteristics. The developed push-pull amplifier demonstrated 53.8-dBm (240 W) output power with 50% power added-efficiency and 12-dB linear gain at 2.12 GHz. It also showed low adjacent channel leakage power ratio (ACPR) of less than -35 dBc with a power-added efficiency of 28% at an output power of 45 dBm. The developed amplifier is suitable for digital cellular base station applications.