Design of the Wideband and Low-Height Omnidirectional Cylindrical Dielectric Resonator Antenna Using Arced-Apertures Feeding

Abstract

This paper mainly discusses the design of wideband and low-height omnidirectional cylindrical dielectric resonator antenna (DRA). It was theoretically found that the TM-mode category of the cylindrical DRA is suitable for the wideband and low-height design using mode-merging method (TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{01 \delta }$ </tex-math></inline-formula> and TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{02 \delta }$ </tex-math></inline-formula> mode). An improved apertures-fed technique is proposed to excite the TM-mode DRA. The feeding consists of four arc-shaped apertures, and each aperture was fed by the in-phase signal. Based on the E-field distribution, the higher-order TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{02 \delta }$ </tex-math></inline-formula> mode of the cylindrical DRA can be excited by adjusting the position of the apertures, and it fuses together with the fundamental TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{01 \delta }$ </tex-math></inline-formula> mode to achieve a wideband antenna. Besides, the aperture mode further widen its impedance bandwidth. To demonstrate the idea, a wideband and low-height omnidirectional cylindrical glass DRA was designed for WLAN 5.2-GHz and 5.8-GHz applications. The experimental results show that the proposed low-height DRA ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$h $ </tex-math></inline-formula> = <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.108\lambda _{0}$ </tex-math></inline-formula> ) can achieve an impedance bandwidth of 25.2 % (without aperture mode) and 34 % (with aperture mode), respectively. The bandwidth enhancement of the proposed design is significant, compared to other reported low-height TM-mode DRAs.