Design of a Wideband Highly Efficient Power Amplifier Using Spoof Surface Plasmon Polaritons Matching Structure

Abstract

In this article, a combination of a power amplifier (PA) and spoof surface plasmon polaritons (SSPPs) matching networks with broadband response is presented to achieve bandwidth expansion of the PA under the microwave frequency. The proposed SSPP architecture as an output-matching network is designed based on a periodic structure with an L-shaped unit cell. Furthermore, a transition structure with gradient corrugation is specially added to the matching network to achieve the conversion from the quasitransverse electric and magnetic (TEM) mode of the microstrip to the SSPP unit cell while achieving low-loss transmission. To validate the predicted performance, the proposed wideband PA based on the SSPP structure is designed and fabricated using a 10 W GaN device. The test results show that the presented PA achieves a measured bandwidth of 151.2% in the range of 0.5–3.6 GHz while exhibiting an outstanding performance of 9–11.8 dB gain, 61.1%–73.3% drain efficiency (DE), and 39–41.8 dBm output power throughout the entire operating frequency band.