Compact and Low-Profile Linear-/Circular-Polarization Dielectric Resonator Antennas With Extended Bandwidths

Abstract

The dielectric resonator antenna (DRA) with wide bandwidth, compact size and low profile is considered as an attractive candidate for 5G wireless communications. However, most of the reported DRAs either have bulky volumes or have limited bandwidths. In this paper, a kind of compact and low-profile DRA with extended bandwidth is proposed. By observing the E-field distribution differences between the two target modes and modifying the dielectric characteristics (such as material and dimension) of the designated region where the E-field is very weak for fundamental TE111 mode but quite strong for high-order TE131 mode, the frequency of TE131 mode can be significantly affected and shifted down to merge with that of TE111 mode which is less affected. As a result, extended operating bandwidth can be obtained. This technique also benefits from not having to enlarge the planar size of the high permittivity DR, therefore making the antenna compact enough for 5G beam-scanning and low profile applications. For demonstration, linear- and circular- polarization antenna prototypes were designed and measured. The LP antenna has a −10 dB impedance bandwidth of 17.3% and a peak gain of 7.1 dBi while the CP antenna achieves a 3-dB axial ratio (AR) bandwidth of 12% and a peak gain of 6.6 dBic. Both the antennas have compact volumes of no larger than $0.35{\lambda } _{0} \times 0.35{\lambda } _{0} \times 0.11{\lambda } _{0}$ . Based on the LP and CP antenna elements, two $1\times5$ antenna arrays with the capability of beam scanning are designed and simulated. Wide scanning angles of ±45° and ±40° can be obtained for the LP and CP arrays, respectively.

Keywords

• Beam-scanning
• circular polarization
• compact
• dielectric resonator antenna
• linear polarization
• low-profile