Differentially Fed Wideband Rectangular DRA With High Gain Using Short Horn

A differentially fed rectangular dielectric resonator antenna (DRA) is presented. The DRA is excited by a microstrip gap between two identical transmission lines carrying a differential signal. It is shown that this new method can be adopted to excite the fundamental TE1δ1 mode in a rectangular DRA. Furthermore, by adding a stub to each transmission line, an additional nonradiating resonance is obtained that results in bandwidth enhancement. A conventional hybrid (rat-race) coupler is used for a single-end operation. A common ground plane is shared between the DRA (placed in +z-plane) and the hybrid coupler (placed in -z-plane) to preserve the footprint of the antenna. For |S₁₁| ≤ -10 dB, a wide impedance bandwidth of 30% is measured from 2.27 to 3.07 GHz. Additionally, a surface-mounted short horn (SMSH) is incorporated to enhance the boresight gain throughout the band. In measurements, an optimum boresight gain of 12.2 dBi with an improvement of 5.8 dB is obtained at 2.6 GHz using the proposed DRA with SMSH.