Design of Wideband Dual-Polarized Metasurface Antenna Using Characteristic Mode Analysis

A wideband dual-polarized metasurface antenna is proposed using characteristic mode analysis (CMA) for Ka-band applications. To achieve the dual-polarization, a primary patch is introduced with orthogonal microstrip-feeds in the same layer with a low profile, low cost and low back lobe level. Furthermore, the single-feed and differential-feed are adopted for vertical polarization (VP) and horizontal polarization (HP), respectively, to enhance the port isolation. A $2\times 2$ metasurface is presented for wideband operation and the CMA is used to determine the modal behaviors of the entire structure. Simulation results show that the return losses of both ports are better than 10 dB and the isolation is higher than 20 dB over 30.1-39.6 GHz. The simulated gain ranges 4.7-6.9 dBi and 7-7.5 dBi for VP and HP, respectively.