A structural body comprising: an electromagnetic bandgap, EGB, structure, wherein the EGB structure comprises: a first conductor; a second conductor that is formed in a layer different from a layer in which the first conductor is formed, and that faces the first conductor; and unit structures, each unit structure comprising: a first transmission line that is formed in a layer different from the layers in which the first conductor and the second conductor are formed, that faces the second conductor, and that has one end being an open end, a first conductor via connecting the other end of the first transmission line and the first conductor, and a first and a second capacitance imparting member (112; 105A, 105A') connected to the first transmission line at an intermediate portion being a portion other than both ends of the first transmission line and that form capacitances between the capacitance imparting members and the second conductor, wherein the first capacitance imparting member (112; 105A) is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 1/16 of the length of the first transmission line and is equal to or smaller than 1/3+1/4 thereof, and wherein the second capacitance imparting member (112; 105A') is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 3/8 of the length of the first transmission line and is equal to or smaller than 2/3+1/8 thereof. a first conductor; a second conductor that is formed in a layer different from a layer in which the first conductor is formed, and that faces the first conductor; and unit structures, each unit structure comprising: a first transmission line that is formed in a layer different from the layers in which the first conductor and the second conductor are formed, that faces the second conductor, and that has one end being an open end, a first conductor via connecting the other end of the first transmission line and the first conductor, and a first and a second capacitance imparting member (112; 105A, 105A') connected to the first transmission line at an intermediate portion being a portion other than both ends of the first transmission line and that form capacitances between the capacitance imparting members and the second conductor, wherein the first capacitance imparting member (112; 105A) is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 1/16 of the length of the first transmission line and is equal to or smaller than 1/3+1/4 thereof, and wherein the second capacitance imparting member (112; 105A') is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 3/8 of the length of the first transmission line and is equal to or smaller than 2/3+1/8 thereof. a first transmission line that is formed in a layer different from the layers in which the first conductor and the second conductor are formed, that faces the second conductor, and that has one end being an open end, a first conductor via connecting the other end of the first transmission line and the first conductor, and a first and a second capacitance imparting member (112; 105A, 105A') connected to the first transmission line at an intermediate portion being a portion other than both ends of the first transmission line and that form capacitances between the capacitance imparting members and the second conductor, wherein the first capacitance imparting member (112; 105A) is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 1/16 of the length of the first transmission line and is equal to or smaller than 1/3+1/4 thereof, and wherein the second capacitance imparting member (112; 105A') is attached to the first transmission line at a position the distance of which from the open end is equal to or larger than 3/8 of the length of the first transmission line and is equal to or smaller than 2/3+1/8 thereof.