Electron-Sheet Metasurfaces for Reconfigurable Beam Patterns

Here, a beam-steering structure based on the interaction of antenna radiation with an electron sheet with swiftly moving electrons with a constant velocity is proposed and studied theoretically. Such electron-sheet metasurface, while uniform and homogeneous in its composition, has a dynamic surface conductivity that exhibits nonlocal response that is dependent on the tangential component of the wave vector impinging on it, and may offer a nonsymmetric conductivity distribution with respect of this wave vector component. As a result, asymmetric radiation patterns may be generated from a single magnetic current line source in the presence of such a metastructure. This effect, introduced by the electron sheet with fast-moving electrons on the radiation properties, can be tailored by modifying the number density and the constant velocity of these electron sheets. We explore the effects of the electron-sheet metasurface on the far-zone radiated field in the presence and absence of a perfect electric conducting ground plane. Some of the electromagnetic features, such as the tilt of radiation pattern in the far zone and the field distribution in the near zone, are also discussed. We envision that this reconfigurable beam steering method may find potential applications in THz, microwave, and optical technologies.