Implementation of Synthetic Material in Dielectric Resonator-Based Filtering Antennas

Design of a broadband filtering antenna, by utilizing a dielectric resonator (DR) also as the radiator, is proposed and experimentally verified in this communication. The relationship between the parameters of a DR and its external quality factor (Q
_EXT
) is explored. Results obtained from this exploration indicate that a broad bandwidth of 15.5% is achievable for a filtering antenna (second order, RL <; 15 dB) using a DR as the radiator. In order to achieve the Q
_EXT
values required in different design specifications, the utilization of synthetic material with air-filled holes is proposed to continuously adjust Q
_EXT
of a DR antenna. The above-mentioned two steps also enable the synthetic DR to not only act as a radiator but also the last resonator of a bandpass filter. A second-order prototype is demonstrated at X-band with a center frequency of 11 GHz and a bandwidth of 950 MHz. For both S-parameter and far-field results, a good correspondence is achieved between simulation and measurement.