Class iCGF^–1 Mode Power Amplifier for Enhancing the Linearity of the Traditional Continuous Class F^–1 Mode

ABSTRACT In this paper, the iCGF −1 mode is proposed to compensate the amplitude‐to‐amplitude modulation (AM/AM) distortion of the traditional continuous class F −1 mode while maintaining the high efficiency. The AM/AM profile of the iCGF −1 mode is mathematically expressed simultaneously as a function of the input nonlinearity parameter and conduction angle , which makes the iCGF −1 mode more flexible in controlling the AM/AM profile. The first inflection point of the AM/AM profile can be moved to a higher output power level through theoretical deduction by adjusting the second harmonic source impedance and gate bias voltage to increase the values of and . This flattens the AM/AM profile while the efficiency profile remains almost the same as that of the traditional continuous class F −1 mode. The performance of the iCGF −1 mode is verified through simulation and experimental measurements. The iCGF −1 PA is fabricated with CGH40010F and has a frequency range of 2–2.6 GHz. The drain efficiency is 70.1%–77.9%, and the output power is 41.1–41.7 dBm. The linearity is tested with a 100 MHz 5G NR signal (the peak average power ratio (PAPR) is 8.5 dB) at 2.3 GHz. The worst adjacent channel power ratio (ACPR) is −32.3 dBc without digital predistortion (DPD) and −52.1 dBc with DPD. The results show that the iCGF −1 mode has successfully compensated the AM/AM distortion of the traditional continuous class F mode and maintaining high efficiency.