A reflective broadband metasurface-based cross-polarization converter (CPC) for Ku and K bands

This study presents a broadband cross-polarization conversion metasurface (CPCM) designed for operation in the Ku and K bands. The CPCM unit cell consists of an octagonal ring with two diagonal parasitic arms, which extend within the ring and are thickened with a curvature on the top surface of a substrate, backed by a copper layer. The metasurface efficiently converts a linearly polarized incident electromagnetic (EM) wave into its cross-polarized counterpart over an ultra-wideband frequency range of 13.4–33.6 GHz. The polarization conversion ratio of the proposed structure exceeds 87% at the operating frequencies for normally incident waves and remains above 80% in a Ku band for angles up to 30° for both TE (transverse electric) and TM (transverse magnetic) polarized EM waves. The surface current distribution was thoroughly examined to explain the high-efficiency and ultra-broadband cross-polarization conversion. A good agreement was observed between measured and simulation results, indicating the promising potential of this structure in applications, such as polarization-controlled devices, stealth surfaces, and antennas.