Design of Filtering Dielectric Resonator Antenna Arrays Using Simple Feeding Networks

A 1
$\times $
3 filtering dielectric resonator antenna (DRA) array is investigated in this communication. The central DRA is excited by a microstrip-coupled slot, while the two side DRA elements are, respectively, excited by the central DRA via a low-profile patch-loaded dielectric bridge laid between them. In order to integrate the filtering function, the open stub of the microstrip feed line is elaborately designed to generate a radiation null at the upper band edge, while two vertical metallic strips are added onto the sidewalls of the central DRA to provide another radiation null at the lower band edge. On the other hand, in order to achieve an enhanced gain in the operating passband, the higher order TE
₁₁₃
mode of the DRA elements is excited. It is found that due to the loading effects of metallic patches and conformal strips, three stepping resonances of the TE
₁₁₃
mode are generated in the passband, leading to a wide impedance bandwidth of 13.7% and a stable gain of 11.4 dBi. As a result, both good radiation and filtering performance are achieved without requiring complex filtering circuits. To demonstrate the extensibility of the array, a larger 3
$\times $
3 filtering DRA array with a high peak gain of 14.7 dBi is further designed by just using a three-way power dividing network.