In accordance with an embodiment of the present invention, an electromagnetic bandgap structure includes a plurality of conductive plates, and a multi-via connection part, which electrically connects any two of the plurality of conductive plates with each other. Here, the multi-via connection part includes: a first multi-via, including a first via, having one end part connected to one of the two conductive plates, and at least one other via connected in serial to the first via through a conductive trace; a second multi-via, including a second via, having one end part connected to the other of the two conductive plates, and at least one other via connected in serial to the second via through a conductive trace; and a conductive connection pattern, connecting any one of the vias included in the first multi-via and any one of the vias included in the second multi-via with each other.