There are provided a plurality of connection auxiliary means 12 electrically connected to an end portion of a central conductor 8 of a coaxial track 5 on a side of a patch conductor 3, and radiately extending toward an edge portion of a penetrating hole 7 on a side of the patch conductor 3. The plurality of connection auxiliary means 12 are fitted to or electrically connected to the edge portion of the penetrating hole 7 with an electrically conductive adhesive.