Three-Port Pattern- and Polarization-Diversity Rectangular Dielectric Resonator Antenna

In this communication, a compact three-port pattern- and polarization-diversity rectangular dielectric resonator antenna (DRA) is investigated. The antenna is designed based on three TE modes, $\text{TE}^{x}_{\delta 11}$ mode, asymmetric $\text{TE}^{y}_{1\delta 1}$ mode, and the presented quasi-omnidirectional mode, symmetrical $\text{TE}^{y}_{1\delta 1}$ mode. The radiation mechanism of the presented symmetrical $\text{TE}^{y}_{1\delta 1}$ mode is revealed by the theory of array and the geometric theory of diffraction. The asymmetric and symmetrical $\text{TE}^{y}_{1\delta 1}$ modes are supported by different boundary conditions. Based on the field-distribution difference between the two modes, an artificial boundary made of metal strips is electroplated on a portion of the side of the DRA to excite the symmetric and asymmetric $\text{TE}^{y}_{1\delta 1}$ modes simultaneously. For verification, a three-mode diversity DRA $^{^{^{}}}$ is designed at 5.8 GHz. The $\text{TE}^{x}_{\delta 11}$ , asymmetric, and symmetric $\text{TE}^{y}_{1\delta 1}$ modes are excited by differential probes, slot in the center, and slots at the periphery, respectively. The overlapping 10-dB bandwidth of the three ports covers from 5.7 to 5.9 GHz. The envelope correlation coefficients and mean effective gain ratios are lower than 0.13 and 1.5 dB, respectively.