A broadband differential-fed dual-polarized hollow cylindrical dielectric resonator antenna (DRA) is proposed in this article. It makes use of the HEM111, HEM113, and HEM115 modes of the cylindrical hollow DRA. The proposed DRA is simply fed by two pairs of conducting strips and each pair of strips is provided with the out-of-phase signals. After introducing four disconnected air holes into the DRA, a broadband characteristic is achieved, with little effect on the antenna gain of its higher-order modes. To verify this idea, frosted K9-glass is applied to fabricate the hollow cylindrical DRA. The differential S-parameters, radiation patterns, and antenna gain of the DRA are studied. It is found that the proposed differential-fed dual-polarized DRA is able to provide a broad differential impedance bandwidth of ~68% and a high differential-port isolation better than ~46 dB. Moreover, symmetrical broadside radiation patterns are observed across the whole operating band. The proposed DRA covers the frequency bands including the 5G-n77 (3.4–4.2 GHz), 5G-n79 (4.4–5.0 GHz), WLAN-5.2 GHz (5.15–5.35 GHz), and WLAN-5.8 GHz (5.725–5.825 GHz), which can be used for 5G communications.
On the design of differential loudspeaker arrays with broadside radiation patterns
