Arbitrary manipulations of dual harmonics and their wave behaviors based on space-time-coding digital metasurface

TL;DR

This paper introduces a space-time-coding digital metasurface capable of independently manipulating two harmonic waves simultaneously, enabling advanced control over electromagnetic wave behaviors for applications like radar and wireless communications.

Contribution

It presents a novel method for independent dual-harmonic manipulation using space-time-coding metasurfaces, expanding wave control capabilities beyond existing techniques.

Findings

Successful independent beam shaping at two harmonic frequencies

Analytical theory matches experimental results

Potential applications in cognitive radar and multi-user communications

Abstract

Space-time modulated metasurfaces have attracted significant attention due to the additional degree of freedom in manipulating the electromagnetic (EM) waves in both space and time domains. However, the existing techniques have limited wave control capabilities, leading to just a few feasible schemes like regulation of only one specific harmonic. Here, we propose to realize independent manipulations of arbitrarily dual harmonics and their wave behaviors using a space-time-coding (STC) digital metasurface. By employing different STC sequences to the reflection phase of the metasurface, independent phase-pattern configurations of two desired harmonics can be achieved simultaneously, which further leads to independent beam shaping at the two harmonic frequencies. An analytical theory is developed to offer the physical insights in the arbitrary dual-harmonic manipulations of spectra and spatial beams, which is verified by experiments with good agreements. The presented STC strategy provides a new way to design multifunctional programmable systems, which will find potential applications such as cognitive radar and multi-user wireless communications.