Broadband Multimode Antenna for Sub-6 GHz Base Station Applications

Abstract

─ In this paper, a novel dual-polarized multimode antenna is presented for sub-6 GHz base station applications. Two pairs of slotted patches act as the main radiator to excite two modes, and they are coupled with each other to bring the resonant frequency of the two modes together. Two baluns are orthogonally placed between the main radiator and the ground plane for impedance transforming and introducing a new mode at the lower frequency. The ends of the slotted patches are connected with a reversed T-shaped dipole to optimize the current path and introducing a new mode at the higher frequency. Measured results show that the prototype antenna can achieve a 15-dB impedance bandwidth of 2.30 ~ 3.96 GHz (53.1%) and an average gain of 9.67 ± 0.33 dBi in the operating band. The isolation is greater than 28.0 dB with a half-power beamwidth of around 64° among the operating frequency band. The proposed antenna can be a promising candidate for the fifthgeneration communication in the sub-6 GHz band. Index Terms ─ Base station antennas, broadband antenna, multimode antenna.