Abstract: Surface wave and the coupling between the arrays were always the main problems in the design of conformalantenna. This paper presents a new type of cylindrical EBG structure applied to conformal patch antennas, this structure used thehole-type EBG structure, and the shape of these holes is oval, so that the radiation frequency of the antenna structure falls in theband-stop frequencies of EBG. This could inhibit surface wave radiation and reduce the coupling. Then this paper analyzed theimpact to this antenna from the cell size, the thickness of dielectric layer and the relative dielectric constant respectively.