A compact proximity-fed ultra-wide band patch antenna with four notched-band characteristics: Design and implementation

In this paper, a new printed cedar tree-shaped UWB antenna with four frequency band-rejection characteristics is presented. The equivalent electrical circuit of the antenna is also presented. The antenna is compact volume of size 20 × 20 × 1.5 mm³. Matching between the designed antenna and the 50 Ohm microstrip feed line is manipulated through a proximity-fed technique. Narrow rectangular slits and T-shaped slots are etched in the ground plane to provide four notched bands at frequencies 3.5, 3.9, 5.25 and 5.9 GHz to avoid the interference with the wireless networks which already occupy bands at these frequencies. The antenna is simulated, fabricated. Also an electrical equivalent lumped-circuit is obtained. The experimental data show good agreement with the simulation results along with the equivalent circuit results. The antenna provides almost omnidirectional radiation patterns, relatively stable gain and high radiation efficiency over the entire UWB frequency band excluding the four rejected bands.