Transmission-Reflection-Selective Metasurface and Its Application to RCS Reduction of High-Gain Reflector Antenna

In this article, a novel transmission-reflection-selective metasurface (MS) is introduced to realize symmetric transmission for horizontal-polarized (x-polarized) waves but asymmetric reflections for vertical-polarized (y-polarized) waves propagating along opposite directions. Based on the theoretical analysis, the proposed MS is finally engineered to transmit x-polarized wave but anomalously reflect y-polarized wave for forward direction. As for backward direction, the designed MS acts as a polarizer grating capable of transmitting x- but specularly reflecting y-polarized wave. As an example of its practical application, the designed MS is applied to form a folded reflector antenna with a reduced backward radar cross section (RCS). Both the MS and the folded reflector antenna are numerically simulated, physically implemented, and experimentally measured. The measured results of the folded reflector antenna coincide well with the simulated ones, showing a peak gain of 23.1 dB and a 3 dB gain bandwidth of 29.3% (12.8-17.2 GHz), as well as a -20 dB cross-polarized level bandwidth of 41.6% (11.4-17.4 GHz). Furthermore, the backward RCS of the antenna can be reduced from 11.2 to 18.4 GHz (48.6%) for y-polarization and 14.1 to 16.2 GHz (13.9%) for x-polarization, with the bandwidth defined by RCS reduction higher than 10 dB. The proposed MS and its application to backward RCS reduction of high-gain antenna may promote the uses of metamaterials to many real-world applications.