Multi-functional, multi-band, low-profile, ultra-thin, and cost-effective metasurface-based polarization converter

This article presents a polarization converter (PC) that demonstrates linear polarization (LP) to LP (LP–LP), circular polarization (CP) to CP (CP–CP), and LP to CP (LP–CP) conversion performance in microwave C-band (4–8 GHz), X-band (8–12 GHz), Ku-band (12–18 GHz), and K-band (18–27 GHz). The designed converter performs LP–LP conversion in the frequency ranges of 6.414–6.771 GHz, 10.681–12.160 GHz, and 18.093–19.045 GHz, CP–CP conversion in the same frequency ranges (6.414–6.771 GHz, 10.681–12.160 GHz, and 18.093–19.045 GHz), and LP–CP conversion in the frequency ranges of 7.374–9.414 GHz and 13.792–16.777 GHz. It is single-layer, metasurface-based, reflection-type (because it consists of a metasurface-substrate-metal ground adaptation), multi-band (five bands), multi-functional (because it shows all three LP–LP, LP–CP, and CP–CP conversions), ultra-thin (with a substrate thickness of 1.6 mm (0.034λ)), low-profile, and cost-effective (since relatively cheaper and easily available FR4 dielectric material is used). Simulations for the designed PC have been carried out by the 3D full electromagnetic simulation program — the Computer Simulation Technology (CST) Studio Suite. The performance analysis of the designed converter was carried out according to the reflection coefficients in the frequency range of 4–21 GHz. It was fabricated using the traditional printed circuit board production method, and its performance was validated in microwave X-band by free-space microwave measurements. More information about the conversion mechanism of the converter was also provided by parametric study and surface current analysis. It is observed that the PC design, which has wide angular independence (50°), can be configured to be efficiently used in radar cross section (RCS) reduction and stealth applications.