High-isolation Millimeter-wave Wide-angle Scanning Phased Array U sing Overlapped Metasurface Structure

This manuscript presents a millimeter-wave phased array with the merits of high isolation, low active $\mathrm{S}$ parameters and wide-angle scanning. Firstly, overlapped metasurface structure is proposed to construct a very miniaturized broadband antenna element with the size of only $0.17\lambda_{0}$ . Then, the newly designed element is placed with a small distance of about $0.4\lambda_{0}$ for implementing $1\times 4$ wide-angle scanning phased array. Benefit from the small size of the elements, there are enough space to load decoupling structure for ensuring high isolation. The results show that the array can cover the 5G band from 24.25 to 29.5 GHz with a relative bandwidth of 19.53%, and the isolation between adjacent elements is basically higher than 20dB. Moreover, it can achieve a large scanning range of -61° ~61° in low band and -55°~55° in high band respectively, meanwhile, all the active S parameters can keep lower than -8.4dB for ensuring scanning efficiency. These results reveal that the proposed array would be potentially applied in 5G millimeter-wave communication.