Provided is an antenna module including a plurality of conductive layers stacked in a first direction, the antenna module including a first patch antenna including at least one radiator provided in at least one conductive layer, and an electromagnetic band gap (EBG) structure including a plurality of pillars spaced apart from the at least one radiator in a direction perpendicular to the first direction, the plurality of pillars surrounding the at least one radiator, wherein each of the plurality of pillars includes two or more plates provided parallel with each other in two or more conductive layers, respectively, and at least one via connecting the two or more plates.