A 3.5-GHz, Highly-Efficient Power Amplifier for Wireless Communication Applications

In this paper, we propose a design of a 3.5-GHz class-AB power amplifier that achieves high efficiency. The proposed design, based on Wolfspeed’s CGH40006P GaNHEMT, provides drain efficiency up to 72%. To provide the balance between the maximum output power and amplifier efficiency within the desired bandwidth, source/load-pull simulations are employed. In addition, LC broadband matching, based on equiripple approximation, is applied for input matching while multi-section quarter-wave transformer is used for output matching. The drain bias is designed using a quarterwave transmission line to provide low insertion loss within the desired frequency band. Simulations show that the proposed design provides a small signal gain exceeding 14-dB, fractional bandwidth 28.5%, 38.5 dBm output power, and less than 10 dB return loss in both input and output within the whole bandwidth. The measurements of the implemented power amplifier demonstrate good conformity between simulation and measurement results.