Compact design of quasi-continuous inverse Class-F power amplifier

Abstract:

To address the demands of modern wireless communication systems for radio frequency (RF) power amplifiers (PAs) with high power output, broadband high efficiency, and miniaturization, this study proposes a novel design methodology for broadband high-efficiency PAs suitable for high-power output in the P/L/S bands, with a particular focus on the L band. Firstly, based on the extension of the high-efficiency impedance matching region of continuous inverse Class-F PAs and the impedance characteristics of fundamental low-pass matching circuits, a quasi-continuous inverse Class-F PA impedance model and the corresponding output circuit topology are developed. Secondly, by effectively utilizing the parasitic parameters of large-size transistors in high-power PAs and reusing fundamental and harmonic matching circuit components, the design achieves a compact high-efficiency configuration with minimal components across a wide frequency band, significantly reducing circuit complexity. Finally, to validate the proposed methodology, a prototype PA was designed using a gallium nitride high electron mobility transistor (GaN HEMT) as the primary device, targeting the 1.31.9 GHz frequency band. Experimental results demonstrate a saturated output power of 46.0146.73 dBm and a power gain of 24.0124.73 dB. Moreover, the PA achieves high-efficiency performance, with a power-added efficiency (PAE) of 65.1%69.6% and a drain efficiency (DE) of 74.1%79.5%. Compared with domestic and international PA designs within similar frequency ranges, the proposed approach ensures broadband high efficiency while significantly reducing circuit size and enhancing structural compactness. This design offers a promising solution for miniaturized, broadband, high-efficiency PAs with potential applications in wireless communication, radar systems, and related fields.