Wideband filtering antenna based on zigzag SIW cavities

Abstract In this work, a wideband filtering antenna based on substrate integrated waveguide (SIW) cavities is proposed. The SIW cavities with zigzag topology excite multiple modes to increase the potential filtering bandwidth. The radiation slot etched on the cavity merges the resonant modes into a single frequency band, thereby enabling directional broadband radiation. Moreover, two supplementary slots are introduced to facilitate wideband impedance matching without increasing the overall size. Furthermore, both the cavities and the slots work together to create three radiation nulls, improving the filtering performance. The proposed SIW slot filtering antenna achieves good frequency selectivity and meets the increasing demand for wideband and integration of multifunctional devices. To validate the design, a prototype antenna was fabricated and tested. The measured results show that the prototype has an operating bandwidth of 10.1% at the center frequency of 11.16 GHz. The peak gain within the passband is 6.19 dBi, and the out-of-band radiation rejection level is better than 20 dB.