| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic circuit board of a structure which is selected according to a structure of an electronic circuit on a substrate and which has a high electromagnetic- wave absorptivity. SOLUTION: In an embodiment, the electronic circuit board includes a substrate 1 having a signal line 2 extended on its surface, and a conductive layer 4A formed on a rear surface of the substrate at a grounding potential. The substrate is obtained by mixing 30 volume % or less of magnetic metallic powder of ball-like particles having particle sizes of 0.01 to 10μm and an aspect ratio (of longer or shorter diameter to thickness) of 2 or less with rubber or synthetic resin matrix and by molding the mixture into a plate shape. In another embodiment, the electronic circuit board includes a substrate 1 having a line 2 extended on its surface, and a grounding line 3 extended thereon nearly parallel to the line 2 and having a conductive layer 4B as a power line extended on its rear surface. The substrate is obtained by mixing 30 volume % or less of flat powder of soft-magnetic particles having particle sizes of 0.01 to 10μm and an aspect ratio (of longer or shorter diameter to thickness) exceeding 2 with rubber or synthetic resin matrix and by molding the mixture into a plate shape, in which flat surfaces of the powder particles are dispersed so as to be arranged parallel to the surface of the plate. Even in either embodiment, the substrate is secured to have a specific resistance of 1010Ω.cm or more.
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