| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a circuit board capable of reducing noise levels without changing the layout thereof. <P>SOLUTION: A circuit board 10 includes: an antenna 20 for transmitting and receiving electric waves; a noise source 31; and a closed annular loop-shaped conductor 40 positioned, in the vicinity of the noise source 31, such that the central axis of the loop is in parallel to the direction of magnetic field caused by an electric current flowing through the noise source 31. In the circuit board 10, because a change in density of the magnetic flux generated by the noise source 31 is prevented by a current induced by the loop-shaped conductor 40, current leakage from the noise source 31 into the circuit board 10 is reduced. Consequently, coupling between the noise source 31 and the antenna 20 is reduced, resulting in improved receiving sensitivity of the antenna 20. <P>COPYRIGHT: (C)2012,JPO&INPIT |
