Dual-Band and Dual Wide-Angle Scanning Heterogeneous Metasurface-Based Antenna Array in Large Frequency Ratio Integrating With Millimeter-Wave Phased Arrays in Same Aperture

The manuscript presents a $4\times 4$ Sub-6GHz heterogeneous metasurface-based array integrated with $8\times 8$ millimeter-wave (mmW) phased array within same aperture. Firstly, two heterogeneous Sub-6GHz antenna elements are designed based on a square ring metasurface (SRMS) and an overlapped metasurface (OLMS), respectively. The SRMS-based antenna is stacked above the $8\times 8$ mmW array without occupying additional space, while the feeding networks of the Sub-6GHz and mmW antennas are also integrated together in one package using the low-temperature-cofired ceramic (LTCC) technology. In addition, the OLMS-based antenna offers the same bandwidth and wider beam than the former. Through near-field analysis of the array, phase differences resulting from the height variation among the heterogeneous elements have been compensated. Secondly, the heterogeneous antennas are constructed to a $4\times 4$ Sub-6GHz array, with two $8\times 8$ mmW arrays integrated beneath the SRMS-based elements. To ensure the scanning performance of the heterogeneous Sub-6GHz array, several dummy metasurface (MS) are loaded at sides to enhance radiation while increasing the scanning angle. Besides, a $\pi $ -shaped decoupling paths are loaded between adjacent elements, which can cancel the inherent couplings with scanning efficiency increasing. Finally, the proposed heterogeneous array is fabricated and measured. The $4\times 4$ Sub-6GHz heterogeneous array integrating with the mmW arrays can operate in 3.3-3.6GHz and 24.25-29.5GHz. The array can achieve a wide-angle scanning range from –55° to 55° with high isolation of over 20dB in both bands. Compared with other works, it not only realizes aperture-shared integration of Sub-6GHz phased array and mmW phased array, but also ensure dual-band wide-angle scanning, which can be potentially applied in future multi-band base-station antennas.