A Wideband Circularly Polarized Cubic Dielectric Resonator Antenna Excited With Modified Microstrip Feed

A wideband circularly polarized cubic-shaped dielectric resonator antenna (DRA) was excited with a new question-mark-shaped microstrip feed, which provides two orthogonal modes with a quadrature phase difference, hence generating circular polarization. The proposed antenna offers measured - 10-dB impedance bandwidth of 35.35% (at center frequency 3.14 GHz) and measured 3-dB axial-ratio bandwidth of 20.62% (centered on 3.29 GHz) in the broadside direction. The proposed DRA shows the maximum gain and radiation efficiency of 1.51 dB and 90.65%, respectively, in the operating band. It was observed that the proposed antenna is left-hand circular polarized. This antenna is useful for WiMAX (3.3-3.7 GHz) applications.