Polarization-independent, Single-zero Filtering Transmissive Metasurface with Polarization Conversion Function

In this paper, a transmissive single-zero filter metasurface unit cell with cross polarization conversion function is designed, and furthermore, the four unit cells rotated by
$90^{\circ}$
clockwise are designed as C4 super-structure to achieve polarization independence. The passband of this unit cell is at 2.8 GHz, and the zero point is at 2.6 GHz, the in-band is flat and the out-of-band rejection is very good.