High-permittivity cross-shaped dielectric resonator antenna for circular polarization

Abstract

-This paper presents a wideband circularly polarized (CP) dielectric resonator antenna (DRA). The thin cross-shaped antenna of high permittivity is excited by two orthogonal microstrip lines with 90 • phase difference resulting in circular polarization. The general design principles are proposed in this paper and a commercial full field analysis software, based on Finite-Element-Method (FEM), is employed to fine-tune the proposed antenna. The experimental results show a good agreement with simulation and demonstrate a broadside CP bandwidth of 13.2%.

A Cross-Shaped Dielectric Resonator Antenna for Multifunction and Polarization Diversity Applications

“…5 demonstrates a significant reduction of coupling between these two modes as a result of using a sequential symmetrical feeding. The simulated and measured results validate the concept that an asymmetric feeding (as in [13]) can disturb the symmetric mode distribution and hence increase coupling coefficient between different modes in the DR volume. The coupling coefficient can be reduced by using symmetric feeding.…”

“…Using two feeding points of the cross for CP operation as in [13], the simulation results indicate that the coupling between the CP and LP ports will be more than 10 dB, which is not acceptable for a diversity antenna. This high coupling results from the asymmetrical feeding, i.e., with a feeding point at only one end of each cross arm.…”

“…The wider notch with width provides room for a central probe feed. The detailed design procedures of a similar DR for a 4.5-GHz CP antenna can be found in [13]. For the sake of convenience, the dimensions of the resonator arms, including the notch, are listed in the first three lines of Table I.…”

“…An initial feeding network design for the excitation of the mode is derived from the concept proposed in [13]. In that paper, orthogonal modes were excited in quadrature in the two equal-length dielectric cross arms.…”

“…Compared to [11], the operation of two ports feeding a single-antenna volume with different radiation characteristics is achieved at the same frequency, which results in a multifunction, but also allows diversity. The size of the DR is reduced by using thin plates of high-permittivity material, as successfully applied in dual-mode bridge-shaped DRAs [12] and circularly polarized DRA [13]. In addition, a feeding with sequential rotation technique is utilized to increase the symmetry of the modes and reduce coupling between the two feeding ports.…”