A wideband filtering dielectric resonator antenna based on multipath-coupled parasitic loading structures

A wideband filtering dielectric resonator antenna (FDRA) based on multipath-coupled parasitic loading structure is proposed. An annular slot-coupled feeding structure is employed to excite two adjacent resonances of the cylindrical dielectric resonator, providing the basis for wideband operation. To realize the filtering response, a parasitic C-shaped slot and a grounded short stub are introduced to generate the upper- and lower-band radiation nulls, respectively. In addition, an open stub loaded along the feed line introduces an additional in-band resonance, while a pair of parasitic patches coupled with the C-shaped slot enhances the upper-band coupling strength and produces another in-band resonance. Owing to the multipath-coupled parasitic loading configuration, four in-band resonances and two controllable radiation nulls are achieved within a compact structure. The proposed antenna attains an impedance bandwidth of 21.7% from 1.81 to 2.25 GHz (|S11| <−10 dB), while maintaining a realized gain of approximately 6.19 dBi across the passband. A prototype of the proposed antenna was fabricated and experimentally characterized. The measurement results show good consistency with the simulated results, confirming the validity of the design.