High-Efficiency Broadband PA Design Based on Continuous Class-F Mode with Compression
The paper presents a novel reformulation of the Continuous Class-F (CCF) mode by including an I-V knee scaling equation in the drain current waveform. The device’s knee region scales down the waveform and distorts the ideal flat performances especially when the device is in compression. The output power and drain efficiency are no longer constant across α variation in the CCF mode. Instead, symmetrical performances across α space are simulated and measured showing drain efficiency is at peak when α is at its extreme: +1 or -1. 10W GaN HEMT broadband PA (1.7 GHz to 2.7 GHz) is designed by restricting phase rotation of 2nd harmonic impedances within α=-1 ranges across bandwidth. The manufactured PA achieved 11.3W–18.4W Pout and 65.7%–83.4% DE. When operated with 10MHz LTE signal with 7.6dB PAPR at 2.7 GHz, the PA achieved ACPR levels of -53.6/-54.6 dBc after DPD.