Abstract: A thermally conductive composition is provided, which has a base material; and at least one of a permittivity adjusting filler having a lower permittivity than the base material and a high permeability filler having a higher permeability than the base material. The entire thermally conductive composition has a relative permeability higher than 1 and a relative permittivity of 7 or lower.

Abstract: A printed circuit board includes a printed wiring board having a mounting surface facing a first side, an electronic element provided on the mounting surface, a heat dissipation member disposed on the first side with respect to the electronic element, and a heat conduction member disposed between the electronic element and the heat dissipation member and having a first surface facing the first side and a second surface facing a second side opposite to the first side. The heat conduction member has a high relative magnetic permeability portion and a low relative dielectric constant portion. The high relative magnetic permeability portion surrounds the low relative dielectric constant portion on at least the second surface of the heat conduction member. At least part of the low relative dielectric constant portion overlaps the electronic element in a plan view seen in a direction perpendicular to the mounting surface.

Abstract: A printed circuit board includes a printed wiring board having a mounting surface facing a first side, an electronic element provided on the mounting surface, a heat dissipation member disposed on the first side with respect to the electronic element, and a heat conduction member disposed between the electronic element and the heat dissipation member and having a first surface facing the first side and a second surface facing a second side opposite to the first side. The heat conduction member has a high relative magnetic permeability portion and a low relative dielectric constant portion. The high relative magnetic permeability portion surrounds the low relative dielectric constant portion on at least the second surface of the heat conduction member. At least part of the low relative dielectric constant portion overlaps the electronic element in a plan view seen in a direction perpendicular to the mounting surface.

Abstract: A thermally conductive composition is provided, which comprises: a base material; and at least one of a permittivity adjusting filler having a lower permittivity than the base material and a high permeability filler having a higher permeability than the base material. The entire thermally conductive composition has a relative permeability higher than 1 and a relative permittivity of 7 or lower.

Abstract: A thermally conductive composition is provided, which comprises a base material, and a high magnetic permeability filler having a magnetic permeability higher than that of the base material. The thermally conductive composition further comprises an air region inside, and has a relative magnetic permeability higher than 1, and a relative dielectric constant of 7 or lower.