The heat receiving area H is indicated by a two-dot-one-dash line in FIG. 6. The heat receiving area H is an area in contact with the solder when the ground terminal 464 and the substrate 30 are connected. At the time of soldering, in order to produce a solder back fillet, heat is transferred to the second surface 302. As such, in the present embodiment, as shown in FIG. 5 and FIG. 7, the circuit pattern 41 on the first surface 301, i.e., the soldering surface, is spread wide to better receive the heat from soldering and to assist with the heat dissipation to the second surface 302 (i.e., the non-soldering surface). The inner via 341 also functions as a barrier to limit and/or prevent the heat on the first surface 301 from dissipating toward the center of the first surface 301 of the substrate 30 to better maintain the heat around the ground terminal connection portion 34 and direct the transfer of heat from the first surface 301 to the second surface 302. As indicated near the top of FIG. 7, the right side of FIG. 7 is a direction extending toward the periphery of the substrate 30, and the left side is a direction extending toward the center of the substrate 30.
