Balanced antipodal Vivaldi antenna with novel transition from feeding line to the flares

Designing a balanced antipodal Vivaldi antenna for UWB radar applications is reported in this paper. The antenna operates in the frequency range of 0.3-6 GHz. With the novel concept of overlap-free transition between transmission line and the flares, the operational bandwidth is increased by decreasing the lowest frequency about 30 % while the antenna width is kept constant. The antenna is suitable for such impulse radar as GPR or other impulse radio application thanks to its nearly constant group delay which preserves the excitation pulse shape.