There has been a growing demand for efficient long-range, high-speed supersonic passenger flights. When it comes to supersonic flights, the occurrence of shockwave boundary layer interaction (SBLI) is inevitable, and the repercussions are many. SBLI can occur in numerous aerodynamical instances, such as on the control surfaces of the aircraft, on transonic airfoils, in the nozzles at over-expanded conditions, the supersonic inlets, and many others. The influence of finite width shock generator on the incident shock in the impinging shock wave boundary layer interaction is investigated using different widths of the shock generator. A highly three-dimensional incident oblique shockwave is observed. Experimental and numerical studies are used to understand the nature of three-dimensional shock downstream of the leading edge of the shock generator. The incident shock curved downstream in the streamwise and spanwise direction, and the curvature increased with the decreasing width of the shock generator. The local strength of the incident shock at the bottom wall varied significantly due to this curvature for each of the cases. Consequently, even for shock generators with the same flow deflection, Shockwave boundary layer interaction nature transitioned from separated to non-separated. An explanation and a model for the three-dimensionality of the incident shock are presented, and numerical simulations validate the model. The model shows that the shape of the incident shock is a function of freestream Mach number, flow deflection angle, and the width of the shock generator. Future plans include a study on SBLI with momentum thickness variation and with moving shockwave generator.