Bandwidth Enhancement of Cavity-Backed Slot Antenna Using a Via-Hole Above the Slot

A novel technique for the 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 shortening 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. The fabricated antenna has a 60% wider bandwidth than a cavity-backed slot antenna without a via-hole. The proposed antenna maintains high radiation efficiency and gain, which are characteristics of a conventional cavity-backed slot antenna. The proposed technique is especially useful for enhancing the bandwidth of a cavity-backed slot antenna in a limited area.