A Low-profile Omnidirectional Dielectric Resonator Antenna with Enhanced Bandwidth

Abstract

Antennas dedicated for certain radar and wireless communication applications are required to have a low profile. Dielectric resonator has been widely used to implement different types of antennas due to its unique advantages. Whereas, the contradiction between the low profile and narrow bandwidth limits its application scope. A low-profile omnidirectional vertically-polarized (VP) DRA with shorted metal vias is proposed for bandwidth enhancement in this paper. The proposed DRA is centrally fed by a coaxial probe, exhibiting omnidirectional patterns at 2.4 GHz WLAN band. With the introduction of metal vias, $TM_{02\delta}$ mode of DRA moves to the vicinity of TM01δ mode, thus expanding the bandwidth. The antenna features a 10-dB impedance bandwidth of 8.9% (2.37-2.59 GHz) at its center frequency 2.48 GHz and a low profile of $0.093\lambda_{0}$. Within the whole WLAN band (2.4-2.48 GHz), the realized antenna maintains a stable gain of around 1.8-dBi in the horizontal direction.