Design and Analysis of a Ring Dielectric Resonator Antenna Offering High Gain Over Wide Bandwidth

Abstract

A wideband coaxial-fed ring dielectric resonator antenna (DRA) design is presented, offering uniform high gain over its wide operating bandwidth. The proposed antenna uses a simple, compact, and cost-effective coaxial edge-feeding to achieve a wideband broadside radiation pattern. A comprehensive theoretical analysis is carried out to investigate the role of the substrate in bandwidth enhancement by accurately estimating the resonating frequencies of the ring DRA. To improve the antenna gain, a compact metallic wall is introduced using a small antenna footprint. Experimental results demonstrate an impedance bandwidth of 49.5% (11.55–19.15 GHz). The broadside gain consistently exceeds 15 dBi over the band, reaching a peak value of 15.65 dBi. The proposed antenna exhibits a highly compact profile (2.5λ × 2.5λ × 0.7λ) while simultaneously offering high gain and wide bandwidth. In addition, the antenna exhibits excellent polarization purity, with cross-polarization isolation better than 45 and 35 dB in the E- and H-plane, respectively. Owing to its compact size, wide bandwidth, and high gain features, the proposed ring DRA is well suited for Ku-band high-gain applications and can be extended to higher frequencies.