Highly Efficient Ultrawideband Power Amplifier Based on a Novel Multi-Branch Matching Network

A novel multi-branch structure for designing highly-efficient ultrawideband harmonic-tuned power amplifiers (PAs) with over one octave bandwidth is presented in this letter. The continuous Class-B/J modes are extended to allow a resistive second harmonic impedance as the goal for the design and are combined with the multi-branch structure to achieve the optimal second harmonic impedance matching in a wide frequency band. To verify the validity of the proposed methodology, an ultrawideband PA is implemented and assembled using a commercial 10-W GaN HEMT device. The measurement results show that the drain efficiency (DE) is 56%–70%, the output power is 38–42.3 dBm, and the large signal gain is 8–12.3 dB in the 0.4–3.8 GHz band with a relative bandwidth of 162%.