An Omni-directional elliptical ring dielectric resonator antenna excited with C-shaped feed for wideband applications

In this paper, an elliptical shaped ring dielectric resonator antenna is introduced for wideband applications. For exciting the dielectric resonator, a C-shaped annular microstrip feed network is utilized. Elliptical ring DRA has been loaded on the substrate and symmetrically placed on the C-shaped feed. Due to the asymmetry of elliptical shaped cylinder, two orientation of field configuration can be easily generated in elliptical dielectric designated by even and odd (pre-subscript `e' or `o') wave such as, eHE
₁₁
, eHE
_1δ
, oHE
_2δ
and eHE
_2δ
modes. Merging of several higher order modes leads to enhancement of input impedance bandwidth in the elliptical DRA without removing central part. Further enhancement of bandwidth is done by removing central part of DR to form an elliptical ring DRA, which is our proposed structure. The simulated input impedance bandwidth of elliptical DRA without ring is 67.14% (3.68-7.4 GHz) at center frequency of 5.54 GHz whereas simulated input impedance bandwidth (below -10 dB) of the proposed antenna achieved with ring is 104.06% (2.83-8.97 GHz) with center frequency 5.9 GHz. The proposed antenna provides Omni-directional type of radiation pattern at xz-plane throughout the working frequency band. Simulations are performed using Ansys high frequency simulator structure (HFSS) software 14.0 version. The parametric analysis have been performed for obtaining best values of antenna geometrical parameters such as major axis, minor axis, elliptical ring DRA height, inner radius of C-shape feed network and ground length radius to design wideband antenna for best performance. The proposed antenna provides an antenna average gain of 5.68 dB is with radiation efficiency of approximately 89% throughout the frequency band.