A Highly Miniaturized and Wide Angularly Stable Antenna-Filter-Antenna-Based Polarization Rotating Frequency Selective Surface for Radar Systems

This paper presents a novel polarization rotating frequency selective surface (PR-FSS) design based on the antenna-filter-antenna (AFA) configuration. The proposed design efficiently overcomes the limitations related to miniaturization and wide angular stability in polarization converters currently used in advanced radar systems. The proposed metasurface (MS) features an aperture-coupled design using U- and 90° U-shaped patch elements separated by a 45° slotted ground plane. The incorporation of the particular shape in the proposed design enabled high-efficiency linear-to-linear transmissive cross-polarization (LTL-TCP) conversion and bandpass response, simultaneously. The design concept is initially verified using full-wave electromagnetic (EM) simulations and then validated experimentally. The results showed that the design has stable performance with a wide bandwidth and robust angular response up to 80°. In summary, the prototype offered a consistent polarization conversion ratio (PCR) above 0.95 over the frequency range from 5.18 – 5.72 GHz with a low insertion loss of around 0.4 dB. A good agreement between the simulation and measured results demonstrated the applicability of such miniaturized structures in polarization conversion applications, such as radar systems, to improve target detection and classification.