Ultra-thin, wide-angle and bandwidth-enhanced linear and circular metasurface-based reflection-type polarization converter at X-band microwave frequency

In this study, a low-profile ultra-thin metasurface-based reflection-type polarization converter with enhanced bandwidth for X-band (8.2–12.4 GHz) applications is proposed. The designed converter, which has a cell topology above a substrate (FR-4) material terminated in a metal conductor with overall thickness of 1.2 mm corresponding to a thickness of 0.042λ in terms of wavelength (ultra-thin), indicates the cross polarization performance with a polarization converter ratio (PCR) value of 90% in a wide (9–12 GHz) frequency range (normal incidence) and linear to circular polarization performance with left-handed circular polarization between 8.44 and 8.58 GHz and between 12.74 and 13.14 GHz. It is observed that the converter has a PCR value of 80% for incidence angles up to 60∘. Simulations of the designed converter performed by a commercial electromagnetic simulation program (CST Microwave Studio) were validated by free-space measurements.