Low-Pass Filtering Enabled Design of High-Efficiency Broadband Power Amplifier

Abstract

This paper presents the design and implementation of a high-efficiency broadband power amplifier (PA) that leverages a low-pass filtering-based output matching network to simultaneously achieve wideband performance, harmonic suppression, and efficiency enhancement. The proposed PA employs the CGH40010F GaN HEMT device and operates over the 1.0-3.4 GHz frequency range. A systematic design methodology is followed, integrating stability engineering, loadpull analysis, and distributed-element matching networks. The low-pass filter (LPF)-based output matching network ensures both optimum fundamental impedance matching and strong suppression of the second harmonic. Obtained results demonstrate a broadband drain efficiency ranging from 56% to 70%, a nearly flat saturated output power of 39.3-41.4 dBm, and a stable gain between 8.3-10.4 dB across the band. These results confirm the effectiveness of the LPF-based topology as a practical solution for next-generation broadband wireless communication systems.