Decoupling of Dual-Band Dual-Polarized Base Station Array Antenna

Dual-band dual-polarized arrays (DBDPA) using interleaved configuration have drawn industry attention as a promising way to improve channel capacity in a package that has a minimum width. By integrating high-performance filtering elements, a novel interleaved DBDPA for base station use is presented in this paper. For the first time, a radiation null is introduced into the low-band (LB) antenna using the intrinsic suppression mode of folded dipole. Then, to enhance the gain-suppression level in out-of-band to 16 dB, four rectangular loops are introduced under the radiator. To achieve high selectivity for high-band (HB) antenna, a meander line loop is introduced and analyzed for the first time in this paper. Simulations indicate that the presented HB antenna achieves 17 dB of out-of-band rejection and 243 dB/GHz of roll-off rate. The combined use of these two filtering elements finally enables the realization of a DBDPA with low mutual coupling and low cross-band scattering. According to the measurements, this antenna covers two wide frequency ranges of 2.26–2.73 GHz and 2.98–4.3 GHz with a 25 dB cross-band isolation level.