Abstract
This paper describes an S-band wideband high efficiency power amplifier based on the Nanjing Electron Device Institute's GaAs pHEMT monolithic microwave integrated circuit (MMIC) technology. To realize high efficiency, the two stage power amplifier is designed with a driver ratio of 1 : 8. The low-pass filter/high-pass filter combined matching circuit is applied to the amplifier to reduce the chip size, as well as to realize the optimum impedances over a wide bandwidth for high efficiency at each stage. Biased at class AB under a drain supply voltage of 5 V, the amplifier delivers 33–34 dBm saturated output power across the frequency range of 1.8 to 3 GHz with associated power-added efficiency of 35%–45% and very flat power gain of 25–26 dB in CW mode. The size of this MMIC is very compact with 2.7 × 2.75 mm2.