In the proposed paper Umbrella shaped Dipole antenna is chosen and its radius is optimized for Millimeter wave band, i.e., 60GHz. The Extended dipole is given Microstrip feed and it is backed by Artificial Magnetic Conductor (AMC) ground added with closed cap via holes. In the proposed work the dimensions of Spiral ground and vias are optimized and their combine effects were used to suppress surface wave effect, which were responsible for decrement in the antenna performance in terms of antenna gain and efficiency. The proposed structure is drawn on RT Duriod having permittivity of 2.2 with substrate thickness of 0.45 mm. the results are based on simulation, done using IE3D simulator of Zeland Corporation.