A Novel Dual-Band Concurrent Asymmetric Doherty Power Amplifier for Wireless Communications

Abstract

In this paper, a different dual-band asymmetric Doherty power amplifier (ADPA) with a novel dual-band bandpass filter (DBBPF) with quad-section stepped impedance resonators (SIRs) is presented. This specific DBBPF rejects the annoying frequencies of the second and third harmonics in the dual-band and contributes considerably to performance improvement of ADPA. This structure is confirmed with the design, simulation, implementation and testing of a 10 W GaN-based ADPA for global system for mobile communications (GSM) and worldwide interoperability for microwave access (WiMAX) applications at 1.84 and 3.5[Formula: see text]GHz, respectively. In the measurement results, the ADPA defines a drain efficiency (DE) of 63.7% with an output power of 35[Formula: see text]dBm and power gain is 14.2[Formula: see text]dB, and a DE of 47.5% with an output power of 34.5[Formula: see text]dBm and power gain is 10.4[Formula: see text]dB at the 9[Formula: see text]dB output power back-off (OBO) from the saturated output power in the two frequency bands. Linearity effects, applying 10[Formula: see text]MHz 16 QAM signal and a 5[Formula: see text]MHz WiMAX signal, display an adjacent channel leakage ratio of [Formula: see text] and [Formula: see text][Formula: see text]dBc with the average output power of 36.8/36[Formula: see text]dBm at 1.84/3.5[Formula: see text]GHz, respectively.