Self-Decoupled Dual-Band Dual-Polarized Aperture-Shared Antenna Array

This communication presents a self-decoupled dual-band dual-polarized aperture-shared antenna array. The proposed dual-band array consists of a low-band (LB) antenna element interleaved into a $2\times 2$ high-band (HB) antenna array with compact elements spacing. To mitigate the blockage effect resulting from the LB element, shorted patches are loaded on the LB radiator for suppressing its scattering in the HB frequency range. In addition, high cross-band isolation between the closely spaced LB and HB elements is obtained due to their intrinsic filtering response. Moreover, the in-band mutual coupling between the HB elements is reduced by adding cross-shaped strips on them. As a result, the cross-band and in-band couplings and the antenna blockage effect can be simultaneously reduced without adding an extra decoupling component. A prototype of the proposed array operating in 1.71–2.17 GHz (LB) and 3.3–3.8 GHz (HB) is fabricated and measured. The radiation patterns of the LB and HB elements are almost unaffected by each other. Furthermore, all of the port-to-port isolations are higher than 20 dB. These merits make the proposed design suitable for the multiband base station.