A Broadband and High-Efficiency Polarization-Agile Metasurface Towards Single-Channel Radar Target Discrimination

Dynamic modulation of polarization states via metasurfaces is a key technology for advanced electromagnetic (EM) systems.However, realizing a transmissive architecture that simultaneously offers wide bandwidth, high efficiency, and polarization agility remains a challenge.This paper presents a transmissive, time-varying polarization-agile metasurface (PAM) that converts a fixed linear polarization into sequential polarization states dynamically evolving along the equator of the Poincaré sphere.The design utilizes the transient states of PIN diodes to achieve quasi-continuous amplitude modulation, and incorporates a polarization conversion surface to improve transmission efficiency.Experimental results demonstrate that the metasurface achieves a high transmission efficiency exceeding 78% across a 15% fractional bandwidth (4.8-5.6 GHz).As a proof of concept, the PAM is integrated into a single-channel radar system, demonstrating the discrimination of true targets from high-fidelity false targets.This approach leverages the inherent difference in scattering mechanisms: true targets impose a polarization-varying response, whereas false targets exhibit a fixed polarization determinted by the forwarding device.This work provides a high-performance hardware platform that enables a practical, low-cost approach to enhancing the discrimination capability of single-channel radar systems.