High-Efficiency Broadband Continuous Class-F Power Amplifier Using an Independent Harmonic Termination Load Network

초록

This study developed a new design for a high-efficiency broadband continuous class-F (CCF) power amplifier (PA) that employs an independent harmonic termination load network (IHTLN) to simplify impedance matching in a compact structure. In the CCF operation, the developed IHTLN provides independent, sequential matching at the second- and third-harmonic frequencies while maintaining a robust performance under load impedance variation. The design optimizes transmission line widths to achieve the desired CCF mode impedances at these harmonics, thereby eliminating the need for additional matching stages, minimizing the losses, and reducing the form factor by re-utilizing harmonic networks. To validate the approach, a high-efficiency CCF PA featuring the developed IHTLN was designed, fabricated, and evaluated. The experimental results showed that the fabricated PA achieved a peak power added efficiency (PAE) greater than 50% in the range of 1.85-2.7 GHz, a saturated output power of 40.6-42.5 dBm, and a large-signal gain of 12.1-16.5 dB. Moreover, it realized a peak drain efficiency of 85.8% and a peak PAE of 75.6% at 2.4 GHz. The developed design effectively simplifies broadband impedance matching while precisely controlling harmonic impedances, thereby achieving enhanced efficiency at a targeted frequency without narrowing the bandwidth.

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