An electronic device includes an IC mounted on a substrate and a filter circuit connected to the IC. The filter circuit includes a coil component and a capacitor. The coil component includes a multilayer body, a first coil including a portion of multiple wiring patterns laminated in the multilayer body, a second coil provided on layers different from those of the first coil and including a portion of the multiple wiring patterns, and first, second and third electrodes provided on side surfaces. An opening of the first coil is at least partially overlapped with an opening of the second coil when viewed from a main surface direction. The third electrode is grounded via the capacitor. The first coil has an inductance lower than that of the second coil.

Disclosed herein is a wire that includes: a core wire made of a conductor; an insulating film covering an outer periphery of the core wire; a catalyst adsorption film covering an outer periphery of the insulating film, the catalyst adsorption film including a catalyst serving as a reaction start point of electroless plating; and an outer periphery conductor covering an outer periphery of the catalyst adsorption film.

The disclosure features systems for wireless power transfer that include a resonator featuring a coil with at least two windings and at least one inductor having an inductance value, where the at least one inductor is connected in series to at least one of the windings, and where the inductance value is selected so that when the coil carries a current during operation of the system, the at least one inductor maintains a distribution of current flows among the at least two windings such that for each of the at least two windings, an actual current flow in the winding differs from a target current flow for the winding by 10% or less.

The present invention suppresses leakage magnetic field. A power transfer coil configured to transmit or receive power includes: an inner coil; a first outer coil formed so as to surround the inner coil such that a magnetic flux opposite in phase to a magnetic flux outside the inner coil is generated outside the first outer coil, the first outer coil having one end connected to a first terminal and the other end connected to one end of the inner coil; and a second outer coil formed so as to surround the inner coil such that a magnetic flux opposite in phase to the magnetic flux outside the inner coil is generated outside the second outer coil, the second outer coil having one end connected to a second terminal and the other end connected to the other end of the inner coil.

A filter device includes a dielectric substrate, first and second ground electrodes connected to a ground terminal, and resonators between the ground electrodes and electromagnetically coupled to each other. The ground electrodes are at different positions in a normal direction of the dielectric substrate. Each of the resonators includes a first capacitor electrode partially overlapping with the first ground electrode in plan view of the dielectric substrate, a second capacitor electrode partially overlapping with the second ground electrode in plan view of the dielectric substrate, and a via connecting the capacitor electrodes. The resonators include a first resonator connected to an input terminal, a second resonator connected to an output terminal, and a third resonator between the first and second resonators. Shunt electrodes are connected to the via and the ground terminal in the first and second resonators, respectively.

A filter device includes a body, a ground terminal, and resonators in the body and coupled to each other by electromagnetic field coupling. The resonators include a first resonator coupled to an input terminal, a second resonator coupled to an output terminal, and third and fourth resonators. The second resonator is adjacent to the first resonator in a first direction. The third resonator is adjacent to the first resonator in a second direction perpendicular to the first direction. The fourth resonator is adjacent to the third resonator in the first direction. The third and fourth resonators partially share a path to the ground terminal.

A method of winding a conductor in double pancake, including a first pancake and a second pancake, a reel initially containing the conductor, the method including: a first step in which the reel is placed on a tensioner and a first portion of the conductor is wound around a storage volume; a second step in which a first part of the conductor is inserted in a winding mandrel to change the layer; a third step in which a second portion of the conductor is wound around a first part of the storage volume so as to form a first pancake; a fourth step in which the first portion of the conductor is unwound from the storage volume and is wound around the reel; and a fifth step in which the first portion of the conductor is wound around a second part of the storage volume to form a second pancake.

In a resonant device, a third plane electrode is located between a first plane electrode and a second plane electrode. A first via electrode connects the first plane electrode and the third plane electrode. A second via electrode, a third via electrode, and a fourth via electrode connect the first plane electrode and the second plane electrode. When the third plane electrode is seen in plan view in a normal direction of the first plane electrode, the third plane electrode includes a first projecting portion overlapping with a first area between the second via electrode and the third via electrode, and a second projecting portion overlapping with a second area between the third via electrode and the fourth via electrode.

A transformer (100, 100′) is disclosed, comprising a first conducting element (110) having a first lobed portion (114) arranged to form a first plurality of lobes (116); and a second conducting element (120) having a second lobed portion (124) arranged to form a second plurality of lobes (126); wherein said first lobed portion (114) overlaps said second lobed portion (124) to define a plurality of enclosed areas (130). The transformer is adapted for applications requiring an autotransformer having a weak, negative magnetic coupling coefficient.

A filter device includes a multilayer body in which multiple dielectric layers are stacked, a ground terminal, and a first LC parallel resonator, a second LC parallel resonator, and a third LC parallel resonator located in the multilayer body and magnetically coupled to each other. The first LC parallel resonator includes a first conductor, the second LC parallel resonator includes a second conductor, and the third LC parallel resonator includes a third conductor. The filter device further includes a connection conductor on a layer different from a layer on which the second conductor is located, a first via including one end connected to the first conductor and another end connected to the connection conductor, and a second via including one end connected to the third conductor and another end connected to the connection conductor. The connection conductor includes a first region that overlaps a portion of the second conductor in plan view of the multilayer body seen in a stacking direction.