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 TM
₁₀₁
mode 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 TM
₁₁₁
mode down (close to the TM
₁₀₁
mode) to build an upper band null since the TM
₁₁₁
mode 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.