Design of Multi-Octave Power Amplifier Based on Multipath Harmonic Matching Structure

In this paper, a novel broadband output matching network (OMN) is proposed for the design of extended continuous class-F (ECCF) power amplifiers (PAs) with a bandwidth of more than one octave. This OMN utilizes a multipath impedance matching structure, in which six frequency points in the target band are selected and then efficiently matched to the optimal impedance region provided by the ECCF PA. This approach not only realizes a high-efficiency PA but also extends the bandwidth. To verify the effectiveness of the proposed structure, a PA is designed and implemented using a commercial gallium nitride (GaN) high electron mobility transistor (HEMT). This PA operates from 0.5 to 3.0 GHz, exhibiting a relative bandwidth of 143%. Measured results demonstrate a drain efficiency (DE) of 61.2%–73.9%, an output power (Pout) of 39.5–42.2 dBm, and a gain of 9.5–12.2 dB over the entire operating band.