Input/output terminals 6a, 6b and 6c are formed within portions of cutouts 5a, 5b and 5c provided in a ground conductor 5 on the underside of a magnetic material 3; signal conductors 9a, 9b and 9c are formed within portions of cutouts 8a, 8b and 8c provided in a ground conductor 8 on the top surface of a dielectric substrate 7 at the same places as the cutouts 5a, 5b and 5c of the ground conductor; through holes 10a, 10b and 10c electrically connect a center conductor 4 to the input/output terminals 6a, 6b and 6c; metal bumps 11a, 11b and 11c electrically connect the input/output terminals 6a, 6b and 6c to the signal conductors 9a, 9b and 9c facing each other; and metal bumps 16 electrically connect the ground conductor 5 to the ground conductor 8.