High-Gain, Low-Coupling, Omnidirectional, and Dual-Polarized Dielectric Resonator Antenna Using High-Order Modes

This letter presents a high-gain, low-coupling, omnidirectional, and dual-polarized dielectric resonator antenna (DRA). The high-order TE
_021+δ
and TM
_02δ
modes of the cylindrical DRA are used in the design. The TE
_021+δ
mode is excited by four radial slots with in-phase and equal-magnitude inputs, which produces a horizontal-polarized omnidirectional radiation pattern. A central probe is used to excite the TM
_02δ
mode, which generates a vertical-polarized omnidirectional radiation pattern. The relatively narrow impedance bandwidths of the two high-order modes present a challenge for the design. To solve this problem, the “×” shape and central air layers are introduced at the vertical planes of the E-fields of the TE
_021+δ
and TM
_02δ
modes, respectively, which are found to enhance the impedance bandwidths of the corresponding DRA modes effectively and almost independently. The proposed DRA has an overlapping bandwidth of 7.7%, with a low coupling of −34 dB achieved. Most importantly, it offers a high peak gain of 6.0 dBi.