Arbitrary beam control using passive lossless metasurfaces enabled by orthogonally-polarized custom surface waves

TL;DR

This paper introduces a passive, lossless metasurface design technique that uses orthogonally-polarized custom surface waves to achieve arbitrary beam control, enabling applications like beam steering, guiding, and focusing.

Contribution

It presents a novel design method employing custom surface waves supported by reactive impedance for flexible beam manipulation with passive metasurfaces.

Findings

Design examples include beam translator-reflector, beam launcher, and focusing lens.

The reactive impedance profile can be realized with anisotropic metallic resonators.

The approach supports arbitrary beam control without active components.

Abstract

For passive, lossless impenetrable metasurfaces, a design technique for arbitrary beam control of receiving, guiding, and launching is presented. Arbitrary control is enabled by a custom surface wave in an orthogonal polarization such that its addition to the incident (input) and the desired scattered (output) fields is supported by a reactive surface impedance everywhere on the reflecting surface. Such a custom surface wave (SW) takes the form of an evanescent wave propagating along the surface with a spatially varying envelope. A growing SW appears when an illuminating beam is received. The SW amplitude stays constant when power is guided along the surface. The amplitude diminishes as a propagating wave (PW) is launched from the surface as a leaky wave. The resulting reactive tensor impedance profile may be realized as an array of anisotropic metallic resonators printed on a grounded dielectric substrate. Illustrative design examples of a Gaussian beam translator-reflector, a probe-fed beam launcher, and a near-field focusing lens are provided.