In this paper compact Ultra Wideband (UWB) Vivaldi Tapered Slot Antenna (VTSA) is designed simply by changing its Microstrip to Slot line (M/S) transition. To explain the effect of transition’s shapes on the size and the performance of the UWB VTSA, four models (A–D) with detailed parametric studies are analyzed, designed, and fabricated. As compared to Model A, in Model D the size (42.9 mm × 29.28 mm = 1256.112 mm2) is reduced by 19.25%, and the bandwidth (10.34 GHz) is enhanced by 24.56%, in addition, it provides 6.51 dBi maximum realized gain, and stable end-fire radiation pattern. The validity of the proposed antennas is proven by hardware measurement results.
