Abstract-In this paper an ultrawide bandwidth double-layered Vivaldi antenna (DLVA) integrated in Radome housing is proposed. First the conventional Vivaldi antenna is designed with bandwidth extended from 1.8 to 6 GHz at VSWR (3 : 1). Then for wider bandwidth, two slots are etched in the antenna ground plane to extend the antenna bandwidth from 1.7 to 9 GHz. For more improvement in antenna bandwidth, circular slots as electromagnetic band-gap structure (EBG) are etched to further extend the antenna bandwidth from 1.45 to 10 GHz. For gain enhancement double layers of Vivaldi antenna ground plane are designed with the same feeding line to reach 29 dBi peak. High frequency structure simulator (HFSS) ANSYS is used to design and simulate all the design steps. The proposed antenna is fabricated and measured. Finally, DLVA is integrated inside the Radome to improve the antenna gain and protect the proposed antenna from environmental factors. The antenna is fabricated and tested, and a good agreement between simulated and measured results is found.