Panasonic Intellectual Property Management Co., Ltd.

Takeshi Ichihara

Atsushi Shinkai

Yoshiharu Omori

Kenji Ueno

Kenichi Matsushima

Yoshiharu Oomori

Hideki Tanaka

Masakatsu Nawate

Ryohei Harada

Takuji Kawashima

Nariaki Ishida

A common mode noise filter includes an insulating layer, a first coil conductor disposed on a first surface of the insulating layer and extending slenderly, and a second coil conductor disposed on a second surface of the insulating layer and extending slenderly. The second coil conductor faces the first coil conductor across the insulating layer. A portion of the second coil conductor has a cross section crossing a direction in which the portion of the second coil conductor extends slenderly. The cross section includes an apex portion facing the first coil conductor across the insulating layer and a base side portion opposite to the apex portion. A width of the apex portion is smaller than a width of the base-side portion. The common mode noise filter reduces attenuation of differential signals in high frequencies.

Common mode noise filter

A common mode noise filter includes a laminated body including first to fourth insulating layers stacked on one another, first to fourth coil conductors spirally extending and disposed on upper surfaces of the first to fourth insulating layers, respectively, a first via-electrode connecting the first coil conductor to the second coil conductor, a second via-electrode connecting the third coil conductor to the fourth coil conductor, first and second connection parts connecting the first via-electrode to first and second inner ends of the first and second coil conductors, respectively, and third and fourth connection parts connecting the second via-electrode to third and fourth inner ends of the third and fourth coil conductors, respectively. The first connection part overlaps the second connection part when viewed from above. The third connection part overlaps the fourth connection part when viewed from above. The common mode noise filter is operable in high frequencies.

A common mode noise filter includes a first coil and a second coil. The first coil is formed in a plurality of insulating layers and includes a spiral first coil conductor and a spiral second coil conductor. The second coil is formed in the plurality of insulating layers and includes a spiral third coil conductor and a spiral fourth coil conductor. The first and third coil conductors are magnetically coupled to form a first common mode filter unit, and the second and fourth coil conductors are magnetically coupled to form a second common mode filter unit. As viewed from above, a first direction in which currents flow through the first and third coil conductors in the first common mode filter unit is opposite to a second direction in which currents flow through the second and fourth coil conductors in the second common mode filter unit.

In a common mode noise filter, first coil () includes first coil conductor () and second coil conductor () with spiral shapes. Second coil () includes third coil conductor () and fourth coil conductor () with spiral shapes. First coil conductor (), third coil conductor (), second coil conductor (), and fourth coil conductor () are placed in this order from above. First metal layer () configured to be connected to a ground is provided above first coil conductor ().

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Fukui, Japan

Takeshi Ichihara