Efficient Amplification of Large-Signal Spoof Surface Plasmon Polaritons in a Subwavelength Size

The advancement of communication systems demands ever-smaller sizes, leading to the integration of more circuits in compact forms. A promising solution lies in Spoof Surface Plasmon Polaritons (SSPPs), which enable strong confinement, low interference, and a significant wave vector, thereby facilitating smaller sizes. However, the amplification of large plasmonic signals in a compact size remains a daunting scientific challenge for the further development of SSPPs communication systems. In this study, this challenge is tackled by selecting GaN High Electron Mobility Transistors (HEMTs) and load/source-pull technologies. To ensure efficient operation, impedance-matching networks are designed, resulting in a remarkably small amplifier structure. The approach involves utilizing the Bayesian optimization (BO) algorithm to fine-tune the matching network, leading to exceptional amplification performance. The results obtained in the frequency range of 1-3 GHz are highly promising, with both simulated and measured results demonstrating an impressive output power exceeding 40 dBm, a power added efficiency (PAE) surpassing 60%, and a gain exceeding 10 dB. These remarkable achievements underscore the viability of amplifying large-signal SSPPs and outputting high-power SSPPs waves within a subwavelength size, opening exciting possibilities for SSPPs communication, sensing, and imaging systems. A novel design of a high-power SSPPs amplifier at 1-3GHz utilizing HEMT is presented. The optimized structure is simulated, fabricated, and measured, resulting in an impressive output power exceeding 40 dBm, a PAE surpassing 60%, and a gain exceeding 10 dB. These results dvalidate the proposed design for amplifying large-signal SSPPs and its practical realization for high-power SSPPs applications.image