An electro-magnetic bandgap structure is disclosed. The electro-magnetic bandgap structure in accordance with an embodiment of the present invention includes a plurality of conductive plates bridge-connected with one another on a same plane, whereas the each of the conductive plates includes an internal patch; a first ring patch be electrically separated from the internal patch and surrounding the internal patch; and a second ring patch surrounding the first ring patch and electrically connected with the first ring patch through a portion.