A 2-Bit Pancharatnam-Berry Coding Metasurface for Ultra-wideband and Polarization Insensitive RCS Reduction

Because Pancharatnam-Berry (PB) geometrical phase can only be generated in the co-polarized reflection coefficient under circular polarized (CP) incidence for a reflective metasurface, the design of a reflective PB coding metasurface must be based on an appropriate polarization conversion metasurface (PCM) which can achieve CP-maintaining reflection. In this work, to design a reflective 2-dit PB coding metasurface for radar cross section (RCS) reduction, an ultra-wideband PCM is proposed at first, numerical simulation shows that the PCM can realize ultra-wideband CP-maintaining reflection from 8.6 to 35.9 GHz; moreover, PB phase will be generated in its co-polarized reflection coefficient under CP incidence by rotating its unit structure. Thus, an ultra-wideband reflective 2-dit PB coding metasurface is constructed successfully based on the PCM. The simulation and experiment results show that the coding metasurface has excellent performance in RCS reduction under arbitrary polarized incidences, compared with a pure metallic plate with the same size, its RCS can be reduced more than 10 dB in the frequency band 8.2-35.2 GHz with a relative bandwidth of 124.4%, in addition, the RCS reduction performance is kept well when the incident angle is increased to 45 degrees.

Automated summary

The design of a reflective PB coding metasurface was achieved by introducing an ultra-wideband PCM to enable CP-maintaining reflection, resulting in a successful construction of an ultra-wideband reflective 2-dit PB coding metasurface. Simulation and experimental results demonstrate excellent RCS reduction performance of the metasurface under arbitrary polarized incidences.