A Folded Substrate Integrated Waveguide Cavity Slot Filtenna with Controllable Nulls and Low Cross Polarization

This paper presents a folded substrate integrated waveguide (FSIW) cavity slot filtenna with controllable nulls and low cross polarization. The antenna is composed of a folded substrate integrated waveguide resonant cavity, a radiating slot etched on the top layer, and three types of metal vias. And it utilizes coaxial feeding. The antenna has a center frequency of 5.73 GHz and a 10 dB impedance bandwidth ranging from 5.41 GHz to 6.05 GHz, with a relative bandwidth of 11.17%. It exhibits excellent radiation performance within the frequency band and achieves an out-of-band suppression greater than 20 dB. The isolation between main polarization and cross polarization is greater than -30dB.