Compact Unilateral Circularly Polarized Dielectric Resonator Antenna

A compact circularly polarized (CP) unidirectional dielectric resonator (DR) antenna (DRA) with lateral radiation is investigated for the first time. It requires two sets of CP far fields that have complementary patterns. The first set is obtained using the DR TM_01δ and TE_{01δ +1} mode. For the second set, the CP DR-loaded slot antenna is used, which is realized by a cutting cross-slot in the ground plane. To demonstrate the idea, a CP unidirectional DRA is designed at 2.4 GHz for wireless local area network applications. A prototype was fabricated and tested, and reasonable agreement between the measured and simulation results is obtained. It was measured that its overlapping impedance and axial ratio bandwidth is 4.9% (2.39-2.51 GHz), with a front-to-back ratio of 15.5 dB at 2.44 GHz.