Optically Transparent Coding Metasurface With Dual-Polarization Conversion and RCS Reduction Characteristics

The basic stealth technology techniques are often limited to single frequency bands or single functionality, presenting a challenge for achieving superior stealth performance. In this study, an optically transparent coding metasurface (OTCMS) is designed based on glass and indium tin oxide (ITO) to realize dual-polarization conversion along with radar cross section (RCS) reduction at different frequencies. The fundamental unit, “meta-0,” consists of a diagonal I-shaped ITO resistive pattern that converts linearly polarized incident wave into its orthogonal component in two frequency bands (9.46-11.63 GHz and 15.86-17.28 GHz) with a fractional bandwidths of 21% and 9% respectively, whereas linear polarized incident wave is converted to circular polarized reflected wave in the 12.50-15.26 GHz band, with a fractional bandwidth of 20%. Next, the Pancharatnam-Berry (PB) phase is utilized to generate “meta-1” by simply rotating the “meta-0” with 90° to achieve a 180° phase difference between them. The “meta-0” and “meta-1” are arranged in an array using an optimized coding sequence to form OTCMS for RCS reduction. A reduction of more than 10 dB in RCS has been achieved across dual frequency bands for linearly polarized incident wave from 8.9-11.6 and 15.9-17.7 GHz. A prototype has been fabricated, and experimental outcomes align well with simulated results. This work opens avenues for the development of multifunctional and low-profile devices for applications in stealth jet windows, optical communication, microwave screening and beyond.