Design of a low profile, compact, wide beam and wideband linear tapered slot antenna with a stripline feed meant for radar applications in X-band has been presented. The aim of this study is to investigate the effects of changes in the physical parameters of linear tapered slot antennas on their radiation characteristics. The radiation characteristics of linearly tapered slot antennas with different opening rate (aperture area) parameters are compared. It is observed that increased opening rate of linear tapered slot antenna exhibit wider beamwidth with lower sidelobe level. Stripline-fed Vivaldi antennas are comprised of: 1) a stripline-to-slotline transition; 2) a stripline stub and a slotline cavity; and 3) a tapered slot. The aperture height of slot affect the radiation characteristics, return loss, beamwidth and scan angle are investigated with different opening rate of slot through the use of a commercially available electromagnetic simulation software HFSS by ANSYS. © 2015 IEEE.