Design of broadband hybrid class EF power amplifier based on novel capacitance compensation structure

Abstract

AbstractThe operating frequency of traditional hybrid class‐EF power amplifiers is limited by the drain‐source output capacitance. This article proposes a novel wideband compensation circuit structure (CCS) for the drain‐source output capacitance. The drain of the transistor is connected in parallel with a wideband CCS to obtain the required output capacitance of the transistor, which improves the operating frequency of the hybrid class‐EF power amplifier and maintains high efficiency over a wide frequency band. Meanwhile, the wideband CCS is connected in parallel with the gate of transistor to suppress harmonics, thereby improving output power and efficiency. In order to validate the effectiveness of the proposed structure, a broadband high‐efficiency hybrid class‐EF power amplifier is fabricated by employing the CGH40010F GaN HEMT. The measurements show that the output power is 40.4 to 41.3 dBm, the drain efficiency is 67% to 72%, and the gain is 10.5 to 11.3 dB in the range of 1.6 to 2.6 GHz. The adjacent channel power ratio is under −30 dBc when using 20 MHz LTE signal without digital predistortion.