A Fifth-Order Single-Layer Dual-Band Half-Mode SIW Filtering Antenna With a Multifunctional Single Slot

A novel fifth-order dual-band half-mode substrate integrated waveguide filtering antenna with a multifunctional single slot and seven shorting pins of different sizes integrated into a single layer is presented in this letter. Initially, the fifth-order modes TM3/2,1, TM5/2,1, TM3/2,3, and TM5/2,3have been excited successively by the coaxial feed. Then, seven shorting pins of different sizes have been loaded to reallocate these modes to form dual passband characteristics and generate three transmission zeros. In addition, a multifunctional slot has been etched to improve the out-of-band suppression, and the radiation gain of the second passband has increased approximately by 5.5 dB. Finally, a prototype has been fabricated and measured to validate the design. The measured results show that the proposed antenna has a $-$10 dB bandwidth from 2.49-2.56 GHz and 3.37-3.49 GHz. It has a peak gain of 7.9 and 8.55 dBi within passband, which are in good agreement with the simulated results.