Reconfigurable and Programmable Space Channels for Non‐Reciprocal Electromagnetic Transmissions by Active Metasurfaces

Abstract The Control of spatial electromagnetic (EM) waves has always been an attractive prospect, especially with the emergence of metasurfaces, which introduce additional manipulating methods and degrees of freedom. In this paper, a design is proposed to realize reconfigurable and programmable space channels for non‐reciprocal transmissions of EM waves through the use of active metasurface. The layout of the chessboard pattern is preferred for constructing the metasurface, which is composed of two kinds of meta‐atoms. One type of meta‐atom is independently controlled for the transmission gain, attenuation, and phase shift, while the other type is independently controlled for the transmission attenuation and phase shift only. The use of power amplifiers (PAs) to achieve transmission gain in the meta‐atoms can actualize the performance of non‐reciprocal transmissions. The programmable operations of phase shift and attenuation in meta‐atoms can dynamically establish varied spatial channels. A prototype of the active metasurface is fabricated and measured. In the measurements, multiple types of reconfigurable and programmable non‐reciprocal transmission channels are observed clearly, verifying the validity of the proposed method.