A Low-Profile Filtering Antenna Using Slotted Dense Dielectric Patch

A low-profile filtering antenna using a thin dense dielectric patch (DDP) with a pair of silver-coated slots is investigated in this letter. The dominate TM101mode of the DDP owning the similar characteristics of the traditional microstrip patch is directly excited by the microstrip line for antenna design. The silver-coated slots etched along the polarization direction, as a key technique in the proposed design, can not only generate a lower band radiation null directly, but also shift high-order TM111mode down (close to the TM101mode) to build an upper band null since the TM111mode is nonexcitation and nonradiation. Accordingly, a good filtering performance of the proposed antenna without any additional circuits is obtained due to the two radiation nulls located on both sides of the antenna's operation band. For demonstration, a prototype is implemented and tested. The simulated and measured results are given, showing good agreement.