A Wideband Circularly Polarized Dielectric Resonator Antenna with Filtering Response

Abstract

In this paper, a wideband circularly polarized (CP) filtering dielectric resonator antenna (FDRA) is proposed.The proposed antenna consists of a microstrip-Y-shaped slot line coupled feeding structure and a grooved DRA.The Y-shaped slot line not only serves as an energy coupling structure to excite the orthogonal modes (TE x 111 mode and TE y 111 mode) of DRA, forming the CP radiation effect, but also generates two resonant modes, thereby broadening the antenna impedance bandwidth.In addition, due to the groove engraved on the diagonal of the DRA top wall, the antenna CP performance within the passband is enhanced.Finally, by loading a shorting stub and a spur line on the microstrip feedline, radiation nulls are generated on both sides of the antenna passband, resulting in a quasi-elliptical filter response in the antenna gain curve.To further verify the performance of the antenna design, a prototype CP FDRA is fabricated and measured.The measurement results indicate that the antenna achieves a -10 dB impedance bandwidth of 46.1% (2.67-4.27GHz) and an axial ratio (AR) bandwidth of 23% (3.08-3.88GHz), with an average measured gain of approximately 4.9 dBi.This antenna exhibits high-frequency selectivity and an out-of-band suppression level exceeding 10 dB.