In this project, an ultra wide band antenna is designed with the help of a square shape. By the method of Fractal technique, the square is reduced in the terms of size, volume. The basic structure considered is a square. The iteration function which is to be applied on the generator which is basic structure is obtained by dividing a square into nine squares of equal size. Same small squares are removed and this gives rise to the first order. Process is then repeated for n number of times to get nth iteration. The directivity and gain is same for the fractal square antenna obtained at the second order. For the fractal second order antenna, the frequency attained is 3.1 to 10.6GHz which is simulated in CST Micro wave studio. The same antenna is fabricated and measured with Network Analyzer and the measured results and simulated results are matched. Here the ground technique used for the antenna is half-arc ground plane. We used half arc ground plane because there will be a soft transmission of current from port to feed so that maximum bandwith can be attained even after the reduction of dimension of the antenna.