Perturbation Technique to Improve Purity of Modal Fields in Dielectric Resonator Antenna Resulting in Reduced Cross-Polarized Radiation

Metallic perturbation in a body of a dielectric resonator antenna (DRA) has been explored with a view to improve the purity of modal fields leading to considerable reduction in unwanted cross-polarized (XP) radiations. A coax-fed cylindrical DRA (CDRA) has been examined with a pair of horizontally oriented metal pins protruded symmetrically face to face through it. The concept behind the design has been discussed and established using simulated results followed by a series of experimental verifications. As much as 10 dB reduction in principal plane XP values without affecting the primary radiation has been demonstrated. Purity in the modal fields is accounted for in terms of achieved isolation between co- and cross-polarized radiations, which attains 25-40 dB over 100° beamwidth.