CIRCUIT SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a circuit substrate that facilitates changing of the frequency of electromagnetic interference that is reduced, using a simple structure. SOLUTION: The end part of a conductive pattern 28 with a prescribed length is connected to a power-supply pattern provided in the circuit substrate 10 so as to bifurcate the electromagnetic interference F, propagating in the power-supply pattern into two directions of the power-supply pattern and the conductive pattern 28 (hereinafter, the position is to be described as a branching point). The electromagnetic interference F2directed toward the conductive pattern 28, returns to the branching point again after being totally reflected at the tip part 28A of the conductive pattern 28. Here, since the conductive pattern 28 has a prescribed length such that the phase of the electromagnetic interference F2which returns from the tip part 28A of the conductive pattern 28, and that of the electromagnetic interference F which reaches the branching point after propagating in the power-supply pattern, become mutually reverse, the electromagnetic interference F and the electromagnetic interference F2are combined at the branching point and cancel each other. As a result of this, the electromagnetic interference F occurring in the circuit substrate 10 can be reduced by using a simple open-stub structure. COPYRIGHT: (C)2008,JPO&INPIT