Design of High-Efficiency Multioctave Power Amplifier Based on a New Load Design Space

In this letter, a new load design space is presented based on extended series of continuous inverse modes (ESCIMs) for designing a high-efficiency power amplifier (PA) with multioctave. The proposed load design space is acquired by adding a phase shift parameter into the current waveform formula of ESCIMs to generate a wider complex fundamental and second harmonic admittance spaces, further expanding the operating bandwidth. As a proof of concept, a multioctave PA is designed by using a gallium nitride (GaN) device. The measured results indicate that a drain efficiency (DE) of 60.3%–73.5%, an output power of 39.1–42 dBm, and a gain of 9.1–12 dB can be achieved over 0.8–3.6 GHz with a relative bandwidth of 127.3%.