Design of the Low-Profile Tri-Polarized Diversity Cylindrical Dielectric Resonator Antenna Utilizing High-Order HEM13δ and TM02δ Modes

This communication mainly discusses the design of the low-profile tri-polarized diversity dielectric resonator antenna (DRA). It employs the
${\text{HEM}}_{\mathrm {13\delta }}^{\mathrm {x}}$
,
${\text{HEM}}_{\mathrm {13\delta }}^{\mathrm {y}}$
, and
${\text{TM}}_{\mathrm {02\delta }}$
modes of the cylindrical DRA. Using the dielectric waveguide model (DWM), new solution with a low-profile feature (height-to-radius ratio = 0.17) is found. For the demonstration, a low-profile tri-polarized cylindrical DRA is developed for WLAN 5.8-GHz application, which is fed by four notched slots of nearly a “O” shape. Two sets of slot pairs excite the
${\text{HEM}}_{\mathrm {13\delta }}^{\mathrm {x}}$
and
${\text{HEM}}_{\mathrm {13\delta }}^{\mathrm {y}}$
modes, which generate the broadside radiation patterns with
$y$
- and
$x$
-polarization, respectively. As four slots have in-phase and equal-amplitude inputs, the
${\text{TM}}_{\mathrm {02\delta }}$
mode of the cylindrical DRA can be activated, which produces the omnidirectional radiation pattern with vertical polarization. The result shows that the proposed tri-polarized cylindrical DRA can provide a height of
$0.1\lambda _{\mathrm {o}}$
, which is a new low among the reported tri-polarized DRAs. In addition, the proposed DRA exhibits other advantages, such as high gain, simple processing, and easy integration with the circuit.