Vivaldi antenna is designed to radiate at 2 to 18 GHz. Fig.2 illustrate the layout of a construction Vivaldi antenna by using CST Microwave Studio. This antenna consists of single layer. Upper layer is copper layer which has a thickness 0.035 mm. The other side of the microstrip is a ground plane. In this design, the microstrip line is used as a transmission line that is located at the closed end notch. The length and width in this design is 55 mm x 40 mm.