Ultra-wideband radar cross-section reduction based on phase cancellation

In this study, a 2-bit coding metasurface is proposed, which can achieve ultra-wideband radar cross section (RCS) reduction under arbitrary polarized incidences due to phase cancellation. In the design process of the 2-dit coding metasurface, a novel polarization conversion metasurface (PCM) is proposed at first, which can realize ultra-wideband circular-polarization (CP) maintaining reflection; moreover, when its unit cell structure is rotated by an angle psi, +/- 2 psi Pancharatnam-Berry (PB) phase will be generated in its co-polarized reflection coefficients under CP incidence. Thus, based on the PCM, an ultra-wideband 2-dit coding metasurface is conveniently proposed. Numerical simulations demonstrate that the coding metasurface has excellent RCS reduction performance. Compared with a pure metallic plate with the same size, its RCS can be reduced more than 10 dB under normal incidences with arbitrary polarizations in the ultra-wide frequency band of 6.9-33.1 GHz with a relative bandwidth of 131%. Moreover, when the incident angle is increased to 45 degrees, the RCS reduction performance can be kept well. Finally, one laboratory sample of the coding metasurface is fabricated and measured, a reasonable agreement is observed between the measured and simulated results.