A circularly polarized antenna base on the transparent conformal polarization-conversion metasurface is proposed. The designed meta-surface unit is an ellipse rotating 45 degrees with a rectangular slot. The three metasurface cells are arranged in a group and rotated 90 degrees around the feed antenna. The metasurface is printed on transparent and conformal PET while also possessing low-profile characteristics. By using this method, polarization conversion of the antenna is achieved without damaging the original antenna structure, thus extending the circular polarization bandwidth of the antenna. The simulated and measured results show that the -10 dB bandwidth of the antenna is 3.9-4.7 GHz, the axial ratio is less than 3 dB. The meta-surface effectively expands the circular polarization bandwidth of the antenna from 100 MHz to 800 MHz. The radiation efficiency of the antenna exceeds 60%, and the peak gain is more than 5 dBi. The radiation patterns show that the antenna has right-handed polarization characteristics and obvious directional radiation characteristics. The meta-surface design effectively broadens the circular polarization bandwidth of the antenna, making it suitable for circularly polarized communication systems operating in the C-band frequency range.

Transparent metasurface-loaded flexible antenna for the X-band. The dumbbell-shaped metasurface is a type of polarization conversion unit arranged in a checkerboard pattern. This structure achieves 10 dB Linear polarization radar crosssection(RCS) reduction under vertical incidence within the 9.2- 21.2 GHz range. Attach it to a slotted antenna array powered by a 1-to-4 Wilkinson power divider. The antenna has good radiation characteristics within the bandwidth of the X band. This antenna design boasts a low profile (0.14λ0), flexibility, and interference resistance. In the 0-90° central angle bending scenario, the structure maintains good RCS reduction and antenna radiation properties, while also effectively reducing electromagnetic waves at 0-45° angle, making it highly suitable for wider applications such as detection radar, satellite communications, and medical equipment.

This study proposes and experimentally validates a multifunctional, ultra-wideband polarization conversion metasurface. The design integrates polarization conversion and electromagnetic scattering functions into a single structure, enabling applications in polarization conversion, beam control, and effective reduction of the radar cross-section (RCS). The metasurface achieves linear-to-circular polarization conversion with an axial ratio (AR) of less than 3 dB across dual-band ranges of 14.6–26.8 GHz and 31–33.5 GHz. Additionally, by adjusting metallic resonant rings within the unit structure, cross-polarization conversion with a polarization conversion ratio (PCR) greater than 0.9 is realized in the 13.6–29.8 GHz frequency range, maintaining excellent stability even at oblique incidence angles up to 50°. Leveraging the phase cancellation principle, various coding arrays are designed to precisely control the scattered beams, reducing the RCS by more than 10 dB. The comparison of simulation and experimental results further validates the wide application potential of this polarization converter in fields such as wireless communication, antenna engineering, and radar stealth.