In this paper, parametric analysis and optimization of a 8–18 GHz ultra wide band (UWB) quad-ridged horn (QRH) antenna is presented. As an initial configuration a horn antenna is designed with boxed dimensions of 5.4 × 5.4 × 8 cm as defined in [1]. The gain of the antenna varies between 10 dBi–13 dBi over the entire bandwidth. The co-polarization and cross polarization graphics are presented. It’s expected that, the variation of physical dimensions affects the antenna parameters. To analyze these effects the parametric analysis simulations are performed with ANSYS HFSS software.