A Cross-Polarization Converter Using Guided Wave Inspired Metasurface With an In-Band Notch and High Frequency Selectivity

In this article, a polarization-independent reflective cross-polarization converter with an in-band notch and high frequency selectivity is proposed in S-band using guided wave inspired metasurface. The equivalent circuit mode was also proposed to analysis and demonstrate the design. The metasurface unit cell is composed of three patterned metallic layers, and each layer of the structure is reflection-symmetrical to ensure polarization independence. A folded L-shaped microstrip line on the bottom layer is designed for third-order polarization conversion. Then, in order to eliminate the in-band interference, a U-shaped slot is added to the ground, which introduces an in-band notch and two polarization conversion zeros on each side of the cross-polarized band. The two zeros for polarization conversion out of the cross-polarized band are at 2.039 GHz and 3.853 GHz, respectively. The designed notch frequency is at 2.834 GHz, and the frequency selectivity is 205.93 dB/GHz and 166.96 dB/GHz at lower and upper side of the notch frequency, respectively. The PCR of the cross-polarized bands reaches 99.99% at 2.617 GHz at the lower side and 99.97% at 3.247 GHz at upper side of the notch frequency, respectively. The insertion loss in the cross-polarized band is about 1dB.