Design a Multi-Octave High-Efficiency Power Amplifier Using a Symmetrical Ring-Resonator Filtering Network With a Dual-Ring Embedded Architecture

In this brief, a design strategy for a multi-octave high-efficiency power amplifier (PA) is presented by using a novel completely symmetric ring-resonator bandpass filtering network with a dual-ring embedded architecture. The presented strategy can achieve wideband frequency response and is relatively easy to analyze and implement due to the completely symmetrical structure employed. In addition, odd-even mode analysis and extended continuous Class-F mode are also used collaboratively to complete the bandwidth expansion and efficiency improvement of the PA. To verify the validity of the proposed design strategy, a prototype operating from 0.5 to 3.2 GHz (fractional bandwidth of 146%) is designed and implemented using a commercially available 10W GaN device. The fabricated PA achieves a measured drain efficiency (DE) of 60.8%–73.4% and gain of 9–12.1 dB at a saturated output power of 39–42.1 dBm over the whole operating bandwidth.