A broadside circularly polarized semi-cylindrical dielectric resonator antenna excited with unequal pair of vertical microstrip line

In this paper, a single feed semi-cylindrical shaped dielectric resonator antenna (DRA) has been utilized to generate circularly polarized radiation in broadside direction (Φ = 0°, θ = 0°). The dielectric resonator has been excited with a pair of vertical microstrip lines with unequal length attached to flat surface of semi-cylinder. In the proposed design, the location of vertical microstrip lines are responsible for generation of orthogonal modes in the dielectric resonator (DR) and their unequal lengths are responsible for establishing phase difference between the orthogonal modes resulting in circular polarization. The fundamental mode HE11δ is excited which radiates in broadside direction. Proposed antenna shows — 10 dB input impedance bandwidth of 24.17% in the frequency range of 2.8–3.57 GHz (at center frequency of 3.18GHz). The axial ratio below 3 dB obtained is 7.7% in the frequency range of 3.11–3.36 GHz (at center frequency of 3.23 GHz). The proposed antenna provides excellent radiation pattern with very low cross polar component with an average gain of 5 dB and consistent good radiation efficiency throughout the working frequency band. To analyze the antenna performance, simulations are carried out on finite element method (FEM) based electromagnetic simulator which is Ansys HFSS software version 14.0. The parametric analysis of proposed antenna parameters such as position of vertical microstrip lines, length and width of microstrip lines, height and radius of semi-cylinder and dielectric resonator permittivity has been performed and their values are optimized in order to find out the optimal dimensions to design antenna for best performance.