US Patent 7619577 Open-slot antenna

The open-slot antenna contains a rectangular main metallic plate having a similarly shaped slot, first and second auxiliary metallic plates extended perpendicularly from the main metallic plate for about the same distance, and a coaxial cable connecting to the main metallic plate across the slot. The first auxiliary metallic plate is positioned generally along a middle range of a longer section of the main metallic plate while the second auxiliary metallic plate is positioned to a side of the first auxiliary metallic plate with an appropriate spacing therebetween. The length of the first auxiliary metallic plate is larger than that of the second auxiliary metallic plate.