In this case, although an air-core state is given to an inside of the conductor parts 56 and 58 by having the through hole parts 62 and 64, it may also be constituted so that a conductive material such as a conductive paste or a non-conductive material such as a non-conductive resin is filled into the through hole parts 62 and 64, and so that a constitution of a non-air core is given.