Integrated Control of Radiation and Reflection Waves Based on the Circular-Polarization Metasurface

Abstract Integrated control of electromagnetic (EM) radiation and reflection waves is critically important to meet high demands of wireless service performances in increasingly complex EM environment. Current approaches for modulating both radiation and reflection waves typically require separate design of metasurface and antenna structure, while achieving direct, independent, and flexible control of both wave types through a simple structure remains a significant challenge. Herein, a circular-polarization radiation-reflection-integrated metasurface (RRIM) is proposed to address this issue. Such a RRIM modulates the geometry phase and the propagation phase in tandem to obtain uncorrelated radiation and reflection phase distributions, enabling independent and simultaneous realization of distinct functionalities with orthogonal circularly-polarized states. As a proof of concept, two prototypes are fabricated and measured. One RRIM prototype can achieve dual-beam radiation with arbitrary gain allocation as well as radar cross section (RCS) reduction. The measured gains of the two beams are 19.91 dBic and 25.06 dBic respectively, and the total aperture efficiency is 39.35%. The measured 10 dB RCS reduction bandwidth is 8-12 GHz for co-polarized waves and 10-10.8 GHz for cross-polarized waves. The other RRIM prototype can display two independent holographic images in radiation and reflection channels. The calculated Pearson correlation coefficients of two holograms reach 82.28% and 70.31%. Both the simulated and measured results validate the performances of RRIM. We believe the RRIM has great potentials in wireless communications and radar applications.