An X-band cavity-backed slot antenna using a via-hole above the slot

A novel technique for bandwidth enhancement of a cavity-backed slot antenna is presented. A via-hole located above the slot creates an additional resonance at a higher frequency by shorting the effective length of the slot. The location of the via-hole can be changed to determine the second resonance frequency of the antenna. With proper placement of the via-hole, the bandwidth of cavity-backed slot antenna can be increased. A substrate integrated waveguide technology is adopted to decrease the height of the cavity, and a grounded coplanar waveguide is used as feeding network. The proposed antenna works at the X-band has a 6.8% wide bandwidth and the antenna maintains high gain during the whole band.