Abstract A compact dual band fan shaped antenna with dimension of 40×34×4.8 mm3 is proposed for broadband application in 20- 40 GHz and 50-70 GHz band. Design techniques based on modified Vivaldi Antenna, modified tapered strip line feed and defective ground are used to design the antenna. These techniques help to acquire enhanced bandwidth with overall a small shape of the antenna. Antenna parameters are simulated using CST Microwave studio. The prototype antenna is fabricated using FR 04 material to keep the fabrication cost low, however it is expected that same antenna with substrate like RT Duroid shall give much better radiation performance without any design change of the antenna. The overall dimensions and measured results are similar to simulated results.