In this paper, the authors designed end fire array antenna in a lucid way i.e. instead of designing the entire array, they made use of master/slave boundary conditions and only illustrated a unit cell. Since the master/slave boundary conditions also allows them to change the scan angle. They will need a better radiation load on the top of the antenna than a simple radiation boundary condition. Therefore, they will need to use a PML. They compared its results through HFSS software and can compare its results with any number of elements easily because of using PML (Perfectly Matched Layer).