Design of novel high‐efficient DPA using ACL‐loaded SIR for linearity improvement

Abstract

In this article, a novel high-efficient Doherty power amplifier (DPA) is designed for linearity improvement from 2.1 to 2.4 GHz. The proposed DPA employs a pair of anti-coupled lines loaded with a stepped impedance resonator to replace the λ/4 transmission line in the conventional DPA for harmonic suppression, phase compensation, and impedance transformation. The DPA is simulated, fabricated, and measured. As the measured results show, in the 2.1-2.4 GHz band, the saturated output power is between 43.2 and 44.5 dBm with the saturated gain level between 10.2 and 11.5 dB. The saturated drain efficiency (DE) is between 60% and 70% with DE at 6 dB output power back-off between 38% and 50%. Compared with the conventional DPA, the third-order intermodulation distortion is reduced by 20 dB. The efficiency and gain have also been improved. The proposed DPA is feasible and applicable in modern wireless communication systems.