It has been difficult to suppress electromagnetic wave that propagates within a suspended substrate. The structure according to the present invention is provided with: a first conductor plane and a second conductor plane that are disposed parallel to each other; a dielectric plane that is disposed between the first and second conductor planes via a hollow region so as to be parallel to the first and second conductor planes; a first transmission line disposed on a surface that is of the dielectric plane and that opposes the first conductor plane; and a second transmission line disposed on a surface that is of the dielectric plane and that opposes the second conductor plane, wherein the first transmission line and the second transmission line are electrically connected to each other.