Dualband Cylindrical Dielectric Resonator Antenna Employing HEM_11δ and HEM_12δ Modes Excited by New Composite Aperture

A composite aperture has been conceived to excite cylindrical dielectric resonator antenna (CDRA) simultaneously with two different modes, resulting in broadside radiations at two adjacent bands. Threefold objectives of this investigation includes: (i) to realize HEM12δmode in a practical CDRA without involving any unwanted hybrid mode; (ii) to explore composite aperture type feed, which serves as equivalent magnetic and electric dipoles to launch HEM11δmode and HEM12δmode, respectively; and hence (iii) to achieve a dual-mode dualband CDRA without compromising in any enlargement of antenna dimension. HEM12δmode is a recent introduction by the present authors as a broadside radiating mode in a CDRA, although this investigation demonstrates a practically feasible application for the first time. Systematic study of newly proposed composite aperture is followed by experimental investigation with a set of prototypes operating at S and C bands. As much as 6 dBi gain with 7-8% matching bandwidth for each operating band has been experimentally demonstrated.