A Novel Impedance Matching Network Suitable for Designing High-Efficiency Power Amplifiers

In this brief, a novel impedance matching network (IMN) for designing high-efficiency power amplifiers (PAs) is presented. With this method, the fundamental matching network (FMN) and the harmonic control network (HCN) are incorporated into a single network, which is composed of a $\boldsymbol{\lambda }$ /8 ( $\boldsymbol{\lambda }$ is wavelength) transmission-line (TL) and a $\boldsymbol{\lambda }$ /4 TL. Based on it, the design procedure is more straightforward. Besides, the forbidden regions and feasible regions of the proposed network at the first three harmonics are also analyzed. The results show that the forbidden regions are very small. Finally, as an example, a harmonic tuned (HT) PA is designed and implemented using a GaN HEMT transistor. The measured results demonstrated that the fabricated HT PA working at 3.0 GHz delivers a power-added efficiency (PAE) of 79.2%, a gain of 11.6 dB and an output power ( ${\text{P}}_{out}$ ) of 41.0 dBm.