In a layout shown in FIG. 1 and FIG. 3, for example, at the board terminal 12A of the noise filter NF1 shown in FIG. 2, a resistance value is 36.34 [mΩ], an inductance value is 2.73 [nH], and a capacitance value is 9.60 [pF]. The above-described values are obtained as a result of calculation performed under the following conditions. That is, it is assumed that the wire 11A has a length of 5 mm, a width of 0.4 mm, and a thickness of 60 μm. Also, it is assumed that a thickness of the conductor pattern formed in each of the wiring layer WL2 and the wiring layer WL3 is 35 μm and a thickness of the conductor pattern formed in the wiring layer WL4 is 60 μm. Also, it is assumed that a thickness of each of an insulating layer 14A between the wiring layer WL1 and the wiring layer WL2 and an insulating layer 14B between the wiring layer WL3 and the wiring layer WL4 is 600 μm and a thickness of an insulating layer 14C between the wiring layer WL2 and the wiring layer WL3 is 100 μm.
Under the above-described calculation conditions, a cutoff frequency of the noise filter NF1 shown in FIG. 2 is 0.98 GHz. A noise filter having such a degree of the cutoff frequency can be sufficiently used as a noise filter used in a frequency band of substantially 150 kHz or more and 2 GHz or less. Further, by adjusting a length, a width, or a thickness of the wire 11A shown in FIG. 1, or adjusting the area of the region where the conductor pattern MPc and the conductor pattern MPg face each other, it is possible to easily adjust a cutoff frequency of the noise filter NF1.
