Broadband, Single-Layered, and Optically Transparent Reflective Phase-Shifting-Surface Array for Beam Manipulation and Enhanced Wireless Communications

Abstract

Optically transparent electromagnetic devices play a crucial role in modern society, yet conventional optically transparent millimeter-wave devices suffer from high return loss, limited phase shift, narrow bandwidth, high profile, and low optical transparency. Current materials, fabrication processes, and design methodologies restrict the development of high-performance optically transparent reflective phase-shifting-surface arrays or reflectarrays. To address this, a design concept for broadband, single-layered, and optically transparent reflectarray antennas is reported, which can be integrated with glass windows for beam manipulation and enhanced indoor signal coverage and wireless communications. The proposed reflectarray element employs a single-layered cyclic olefin copolymer (COC) medium as the dielectric substrate, with fine metal line (FML) patterns under 50 µm width to create multi-resonant structures for phase range broadening. This architecture combines multi-resonant phase-shifting elements with minimal FML structures and low-loss COC substrate, achieving exceptional antenna performance while ensuring high optical transparency. Wireless communication transmission experiments validate the functionality and performance advantages of the fabricated optically transparent reflectarray. These results substantiate the immense potential and broad application prospects of the novel optically transparent COC dielectric material, the FML structure, and the proposed design concepts and methods in advancing high-performance optically transparent reflectarrays and related communication systems.