Compact UWB Planar Monopole Antenna

In this letter, a novel ultrawideband (UWB) planar monopole antenna is presented that has variable band-notch frequency characteristic. The triangular-shaped antenna is electromagnetically coupled to the feed microstrip-line on one side of the dielectric substrate, and this line also directly feeds, through a via-hole, a radiating element in the form of a triangular shape in the ground plane. By inserting an equilateral triangular slot in the ground plane, a much wider impedance bandwidth is realized. Furthermore, the dimensions of conductor plane radiating element and the truncated ground plane can be used to tune the antennas´ band-notch and bandwidth characteristics.