Experimental validation of a Ku-band cross-polarization converter and detailed numerical RCS investigation across multiple geometries

This study presents a novel broadband metasurface-based polarization converter unit cell. The proposed structure operates in reflection using a cost-effective and readily available substrate with a thickness of 1.6 mm. Efficient cross-polarization conversion is achieved across the Ku-band (12-18 GHz), K-band (18-27 GHz), and Ka-band (27-40 GHz). The polarization conversion performance of the unit cell is validated through reflection coefficient analyses conducted using Ansys HFSS and CST Microwave Studio, as well as real-time free-space measurements performed on a fabricated prototype. Both numerical simulations and experimental results confirm linear-to-linear polarization (LP-LP) conversion with a polarization conversion ratio (PCR) exceeding 90% over the 13.01-27.36 GHz frequency band. In addition, due to the inherent characteristics of linear polarization converters, linear-to-circular polarization (LP-CP) conversion is achieved within the 11.88-12.19 GHz band. The proposed design maintains its performance with a PCR above 80% at an incidence angle of [Formula: see text] over the 12.78-15.50 GHz and 17.86-21.11 GHz frequency ranges. Following the polarization analysis, the proposed unit cell is reconfigured into a coded metasurface arrangement to investigate its radar cross-section (RCS) reduction capability. In this context, both monostatic and bistatic RCS reduction analyses are systematically examined. The presented work is compared with other studies reported in the literature, demonstrating that, among comparable studies, this work provides one of the most comprehensive RCS reduction simulation analyses using a highly accessible and low-cost substrate.