Design of a Broadband High-Efficiency Hybrid Class-EFJ Power Amplifier

This letter proposes a novel broadband, high-efficiency power amplifier (PA). The high-efficiency characteristics of Class-EF PAs and the large bandwidth advantages of Class-J PAs are effectively combined in the proposed PA. By theoretically analyzing the impedances of traditional Class-EF PAs and class-J PAs, we can consider the possibility of combining these two types of PAs. The conditions that need to be met are derived. In order to verify the effectiveness of the proposed method, a high-efficiency wideband Class-EFJ PA is designed and fabricated by using CGH40010F GaN HEMT. The measurement results demonstrate that the Class-EFJ PA has saturated output power of 40.5-42.7 dBm in 1.2-3.6 GHz. Drain efficiency of 63%-73% was achieved over the same frequency band. The Adjacent Channel Leakage Ratio (ACLR) was also better than -31.2 dBc at an average output power of 35.6 dBm.