Differentially-fed half-Cylindrical Dielectric Resonator Antenna (CDRA) enables two different modes to be excited at the proper phase difference between the two feed lines. For a differential phase of 00, TE0 mode is excited, while for a phase of 1800, HEM12 mode is excited. The cut-plane of the half-CDRA is so placed on the ground plane-backed substrate that the above modes obey the respective boundary conditions. With minor design changes, the DRA can be operated either in single mode or in dual mode. In dual-mode operation, the maximum directivities are 6.9 dB and 4.3 dB, respectively for a differential phase of 00 and 1800, respectively.

The ability of dielectric resonators to support multiple radiating modes of high radiation efficiency has invoked interest in antenna researchers. Out of the lower Q modes of an isolated Cylindrical Dielectric Resonator Antenna (CDRA) (Kajfez et al., 1984), the TM01 and HEM11 modes are the most widely investigated radiating modes (Leung et al., 2012) even though the TE01 has been shown appropriate for both radiating (Mongia et al., 1993) and non-radiating (Hady et al., 2009) purposes. Excitation of the HEM12mode for end-fire type radiation was proposed by Kishk and Glisson (2001), while the broadside operation of the same was studied recently by Guha et al. (2014). Rather than using the modes individually, their simultaneous use enables a variety of applications such as antenna-cum-filter (Hady et al., 2009), direction finder (Hady et al., 2011) and diversity antenna (Fang et al., 2014). The present paper discusses the use of a half-CDRA for dual-mode applications. Ansys HFSS has been used to obtain the results presented in this paper. Second-order tetrahedral mesh element with maximum surface deviations of 0.1 mm-10O, and an aspect ratio of 1.5 are adopted for simulations.

Telecommunications Journal, Half-Cylindrical Dielectric Resonator Antenna (CDRA), Microstrip transmission line, Differential feed, Dual-band DRA.