A Wideband Filtering Dielectric Resonator Antenna Based on the HEM11δ Mode

In this letter, a wideband filtering dielectric resonator antenna (DRA) based on the
HEM
_11δ
mode is proposed with high roll-off rate and flat gain response in the whole passband. The proposed filtering DRA is excited by a simple feed structure composed of a driven ring, a parasitic ring and a driven arc. Each of them can excite the
HEM
_11δ
mode at different resonant frequencies, thus enlarging the impedance bandwidth of the proposed filtering DRA. Since the three resonant frequencies belong to the same mode, stable radiation pattern can be achieved simultaneously. In addition, two radiation nulls are generated near the lower and upper edges of the passband by the feed structure, making the proposed DRA obtain high frequency selectivity. All the three resonant frequencies and two radiation nulls are independently adjustable. A prototype has been fabricated and measured for demonstration, and the measured results are coincided with the simulated ones.