A coil device includes a first coil portion which faces a second coil portion of another coil device and has a conductive wire, and at least one non-magnetic member disposed on an opposite side from a side facing the second coil portion. The non-magnetic member includes an eddy current interrupter for changing a state of an eddy current formed in the non-magnetic member by interrupting a portion of the eddy current.

An adjustable inductor, according to embodiments of the invention, includes a wire coil configured to mount on a first side of a conductive plate. The wire coil is conductive and is a plurality of windings. A core has a first portion and a second portion. The first and second portions are configured with a plurality of grooves for threading engagement with the plurality of windings of the wire coil. The threading engagement attaches the core to the plurality of windings of the wire coil, which results in varied inductance.

A coil device includes a first coil portion which faces a second coil portion of another coil device and has a conductive wire, and at least one non-magnetic member disposed on an opposite side from a side facing the second coil portion. The non-magnetic member includes an eddy current interrupter for changing a state of an eddy current formed in the non-magnetic member by interrupting a portion of the eddy current.

Embodiments of the present invention provide a tunable inductor having a magnetic core which has an air gap. In order to vary the inductance of the inductor, the inductor includes a tuner that is moveable relative to the magnetic core in the vicinity of the air gap. An actuator is attached to the tuner which, upon actuation, moves the tuner relative to the magnetic core to thereby vary the spacing between the tuner and the core in the vicinity of the air gap. The variation of the spacing between the tuner and the magnetic core varies the effective air gap of the overall inductor in the desired fashion.

A three-dimensionally shaped coil can be manufactured at low cost and easily and uses a planar coil array. In the planar coil array, a flexible board comprises: a first planar coil that has a first spiral shape in which a first conductor is wound in a left-handed or right-handed manner with respect to a first center; and a second planar coil in which a second conductor in the same layer as the first conductor formed on the flexible board is wound with respect to a second center in the same manner of winding as the first coil, the second planar coil having an angular misalignment from the first spiral shape, being disposed adjacent to the first planar coil in a predetermined direction, and being electrically connected to the first planar coil. The flexible board is bent, thereby forming a three-dimensionally shaped coil.

A three-dimensionally shaped coil can be manufactured at low cost and easily and uses a planar coil array. In the planar coil array, a flexible board comprises: a first planar coil that has a first spiral shape in which a first conductor is wound in a left-handed or right-handed manner with respect to a first center; and a second planar coil in which a second conductor in the same layer as the first conductor formed on the flexible board is wound with respect to a second center in the same manner of winding as the first coil, the second planar coil having an angular misalignment from the first spiral shape, being disposed adjacent to the first planar coil in a predetermined direction, and being electrically connected to the first planar coil. The flexible board is bent, thereby forming a three-dimensionally shaped coil.