Theory and experiment of three-port polarization-diversity cylindrical dielectric resonator antenna

The three-port polarization-diversity cylindrical dielectric resonator antenna (DRA) is presented for the first time. The design makes use of the TM_01δ and HEM_12δ+1 modes of the cylindrical DRA. Using the covariance matrix adaptation evolutionary strategy, engineering formulas are obtained to determine the dimensions of the polarization-diversity cylindrical DRA for a given operating frequency and dielectric constant. To demonstrate the usefulness of the formulas, a three-port polarization-diversity cylindrical DRA was designed at 2.4 GHz for WLAN applications. The TM_01δ mode of the cylindrical DRA is excited with a coaxial probe and an omnidirectional radiation pattern is obtained. Two slot pairs are used to excite the broadside HEM_12δ+1 ^x and HEM_12δ+1 ^y modes of the cylindrical DRA. The reflection coefficient, port isolation, radiation pattern, and antenna gain of the antenna were simulated using ANSYS HFSS, while the envelope correlation was calculated from the -parameters. Measurements were carried out to verify the simulations, and reasonable agreement between them is observed. Measured results show that the isolation between any two ports of the diversity DRA is over 24 dB across the 10-dB impedance bandwidth. A parameter study was carried out to characterize the proposed DRA.