A Broadband ±45° Dual-Polarized Multidipole Antenna Fed by Capacitive Coupling

A broadband ±45° dual-polarized multidipole antenna is proposed in this communication. A pair of big dipoles and a pair of small ones are printed on a square substrate. The large dipoles mainly dominate the low operating frequency of the antenna, while the small dipoles work at the high one. A pair of H-shaped coupler is introduced to feed the antenna through capacitive coupling with loop radiator dipoles, and a rectangular box-shaped reflector is used for keeping the radiation patterns over the operating frequency. The antenna achieved a wide impedance bandwidth of about 56.6% for <; 1.5 at both ports, covering the frequency range from 1.66 to 2.97 GHz. Over the operating frequency, a gain >8.1 dBi is achieved for both ports. A stable radiation pattern with 3 dB beamwidth 62°±6° at E-plane and 75°±3° at H-plane for port 1 and 60° ±4° at E-plane and 71° ±5° at H-plane for port 2 is obtained. The antenna is manufactured and tested. The measured results of the antenna are in well agreement with the simulation ones. Design details of the proposed antenna are presented and discussed.