A Compact Dual Band Substrate Integrated Waveguide Filtering Antenna using Multi Slot and Defective Ground Structure

A miniaturized dual-band filtering antenna based on a substrate-integrated waveguide (SIW) structure is presented. The structure of the filtering antenna is formed by a rectangular SIW cavity with multiple etched slots and cylindrical vias at the upper part, in which radiation occurs. Inset feeding is implemented to facilitate the effective power coupling and impedance matching. Mode excitation and filtering functionality is facilitated by an inner circular vias and equally placed smaller circular vias and rectangular slots. The Proposed filtering antenna design radiation is intended at 9.25 GHz and 21.25GHz with reflection coefficient as -23.81 dB and -20.52 dB, respectively. The maximum gain is of 6.2 dB and 1.5 dB for both bands. A design prototype is created and S parameters are tested for verifying the design. The antenna comprises two distinct frequency bands, providing good filtering response and high radiation efficiency.