Investigation of Resonant Modes in Wideband Hybrid Omnidirectional Rectangular Dielectric Resonator Antenna

In this paper, resonant modes of the hybrid omnidirectional rectangular dielectric resonator (DR) antenna (DRA) are investigated. It is found that the omnidirectional mode of the rectangular DR is a combination of the higher-order TE^∞₁₂₁ and TE^y₂₁₁ modes. Omnidirectional patterns can be achieved by exciting the TE^∞₁₂₁and TE^y₂₁₁ modes of a rectangular DRA, which has a square cross-section, with equal amplitude and phase. Thus, the dielectric waveguide model (DWM) method can be used to predict the resonant frequency and field distributions of the omnidirectional mode of rectangular DRA. In addition, the resonance of feeding probe is also studied. And a wideband hybrid design is achieved by merging resonances of the rectangular DRA and feeding probe. Full-wave simulations and experimental measurements were carried out to verify the proposed idea. Both the simulated and measured results agree well with the calculated results.