A Novel Two-Stage Broadband Doherty Power Amplifier for Wireless Applications

Broadband and highly efficient amplifiers are of great interest in modern wireless communication systems. In this paper, we present a novel two-stage broadband Doherty power amplifier (DPA), which is able to maintain high efficiency at saturated output power and at backoff output power levels over a wide bandwidth. The amplifier uses a novel and simple approach to achieve bandwidth enhancement and at the same time uses a driver amplifier. We employ Klopfenstein taper to deliver wide bandwidth. The measurement results show that the proposed broadband two-stage DPA is able to deliver 31%–35% drain efficiency at 6-dB output power backoff while at the saturation it achieves 40%–55% drain efficiency over the designed bandwidth of 1.5 to 2.6 GHz. The amplifier can deliver above 35-dBm output power with substantial gain of around 20 dB. The proposed DPA is a promising candidate for wideband and high gain requirements in modern wireless systems.