| 摘要 |
Provided are: a circuit substrate with which an increase in the size of the area allocated to electromagnetic band gap structures formed from spiral open stubs can be inhibited, and mounting space can be utilized more effectively, even in cases when the frequency of the electromagnetic noise to be reduced is set so as to be further towards a low frequency side; and a noise reduction method for the circuit substrate. The circuit substrate of the invention of the present application is provided with: a core substrate; a reinforcing dielectric layer provided to one surface of the core substrate; first electromagnetic band gap structures which are provided to either of the surfaces of the reinforcing dielectric layer, and which suppress electromagnetic noise of a prescribed first frequency propagating in the core substrate; and auxiliary patterns which are formed around the outer peripheries of patterns forming the first electromagnetic band gap structures, with a prescribed distance therebetween. |
