An antenna cover is used with an antenna for passing therethrough a radiation of the antenna in order to modify an antenna pattern of the antenna. The antenna cover includes a housing having a first surface and a second surface; and a plurality of through holes penetrating through the housing and extending from the first surface to the second surface. By way of adjusting distances between the plurality of through holes and/or adjusting sizes of the plurality of through holes, the antenna cover functions to adjust the radiation of the antenna from a first antenna pattern to a second antenna pattern.