A broadband high efficient Class-J power amplifier with compact matching network

Abstract

A broadband high efficiency Class-J power amplifier (JPA) with new output impedance calculation method is proposed. A compact low-pass output matching network and an opened-sector microstrip line instead of a parallel capacitor are employed to provide impedance space for broadband design. To enhance the bandwidth, a multi-stage Chebyshev low pass matching network is used with input matching network. For demonstration, a broadband high efficient JPA based on proposed structure is designed and fabricated. Measurement results show that the drain efficiency between 55%–67%, output power from 40 to 42.6 dBm with more than 10 dB gain over a bandwidth of 1.0–3.0 GHz, accounting for 100% fractional bandwidth. When employed by a 5 MHz WCDMA signal with 8-dB peak-to-average power ratio (PAPR), the adjacent channel power ratio (ACPR) between −24.1 and −32.4 dBc without digital predistortion (DPD).