Investigation of a New Radiating Mode and the Traditional Dominant Mode in Rectangular Dielectric Resonator Antenna

The TE $_{\delta 01}^{x}$ mode excited in a rectangular dielectric resonator antenna (DRA) with metal coating is presented. This mode was first proposed in a hybrid DRA in our previous work. To compare it to the traditional dominant mode and further show its characteristics, a set of simple rectangular DRAs with and without metal coating was designed, fabricated, and measured in this letter. These DRAs are mounted on the ground plane and fed by a coupling slot. Due to specific field distributions, the TE $_{\delta 01}^{x}$ mode can work at a much lower frequency than the traditional one in the rectangular DRA with the same dimensions. In addition, broadside radiation pattern and good radiation efficiency over the operating bandwidth are also obtained.