Bandwidth-enhanced SIW cavitybacked antenna array using even and odd modes

A novel technique to enhance the bandwidth of substrate-integrated waveguide (SIW) cavity-backed antenna array is presented. The proposed array consists of four SIW cavities connected by inductive windows as feeding network and four wide slots on the surface of each cavity as radiating part. The even-odd mode theory is used to analyse the array. By offsetting the slots from the cavities centre, two different work modes are excited at two resonant frequencies simultaneously and the bandwidth enhancement is achieved by merging them together. A prototype is fabricated to verify the properties of the array. The measured bandwidth can be broadened to 14.5% from 18.25 to 21.1GHz and the maximal gain can reach up to 12.8dBi.