| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit board for use in an electronic apparatus such as an information apparatus, which can stably reduce electromagnetic wave radiation from a power system having general purpose property and a low-cost structure. SOLUTION: This circuit board includes a power layer 11, a grounding layer 12, and a dielectric layer disposed between the power and the grounding layers 11 and 12. In this case, the dielectric layer is constituted of two dielectric materials 13a and 13b, having different dielectric constants for providing a dielectric constant distribution in planes along the power and grounding layers 11 and 12. As a result, resonance conditions are made different at respective positions so as to provide weak resonances distributed widely over a frequency axis, thus reducing electromagnetic wave radiation which has been generated strongly at a specified frequency. |
