COMPOSITE MAGNETIC BODY, ITS MANUFACTURING METHOD, CIRCUIT SUBSTRATE USING THE SAME, AND ELECTRONIC DEVICE USING THE SAME

摘要

It is possible to provide a composite magnetic body having a sufficiently small magnetic loss in the frequency of several hundreds MHz to several GHz and its manufacturing method. The composite magnetic body is formed by dispersing magnetic powder in an insulating material. The magnetic powder has spherical shape or a flat shape. The composite magnetic body has one of the following characteristics (a) to (c): (a) In the frequency of 1 GHz or 500 MHz, the relative permeability µr is greater than 1 and the loss tangent tan d is not greater than 0.1. (b) In the frequency not greater than 1.2 GHz, the complex permeability has a real part µr' greater than 10 and the loss tangent tan d is not greater than 0.3. (c) In the frequency not greater than 4 GHz, the complex permeability has a real part µr' greater than 1; and in the frequency not greater than 1 GHz, the loss tangent tan d is not greater than 0.1.