Dual‐band stacked base station antenna array with high isolation

Abstract

A high-isolation dual-band base station antenna array is proposed. At first, a 5-element high-band (HB) dipole antenna array with inter-element distance of 0.4 λH0 (the free-space wavelength at the center frequency of the HB) is decoupled. With the main antenna decoupling surface (ADS), metal baffles and auxiliary ADS, the E-plane and H-plane couplings can be reduced to <−23.1 dB (<−11.4 dB without decoupling) and <−22.6 dB (<−14.8 dB without decoupling), respectively. The dual-layer ADS design successfully resolves the contradiction between decoupling performance and matching. The ground plane of the 5-element array is then exploited as the low-band patch radiator, forming the proposed dual-band antenna array. Measured results show that satisfactory cross-band isolation (>33.1 dB), in-band isolation (>22.2 dB) and polarization isolation (>30 dB) are obtained. Stable unidirectional radiation patterns are also acquired.