Direct Conversion of Static Voltage to a Steerable RF Radiation Beam Using an Active Metasurface

A low-profile, directive, high-power, simple radio frequency (RF) source can play a crucial role in long-distance communication, sensing, and anti-interference research. Conventional approaches to achieving high-power radiation require a microwave source, an amplifier, and a separate radiating structure. In this article, we transform a static voltage to electromagnetic radiation, which can be electronically steered, using only a thin sheet of metasurface. The proposed approach can be scaled in both power and frequency. The concept makes use of the k = 0 mode in a periodic resonant surface to excite a series of phase-locked individual sources on the surface. The phase-locked sources create an overall coherent mode in the far-field toward the desired direction. The proposed idea is inspired by spark-gap transmitters, pulsed ring-down sources, and antenna arrays to provide a novel and highly scalable electromagnetic source. We envision that the proposed active metasurface for converting a static field to electromagnetic radiation can be potentially used in long-range communication, sensing devices, and radars.