An antenna device includes a core, a bobbin member having a partition, and a coil provided around the bobbin member. The coil is configured with a tight winding portion and a loose winding portion. The tight winding portion is provided between one bobbin side and the partition. The loose winding portion is provided between the other bobbin side and the partition. The loose winding portion is configured with a first winding layer and a second winding layer. A wire winding direction of the first winding layer is opposite to a wire winding direction of the second winding layer so that the wire of the first winding layer and the wire of the second winding layer cross and overlap to each other along part of the bobbin member.

An antenna device includes a core, a bobbin member having a partition, and a coil provided around the bobbin member. The coil is configured with a tight winding portion and a loose winding portion. The tight winding portion is provided between one bobbin side and the partition. The loose winding portion is provided between the other bobbin side and the partition. The loose winding portion is configured with a first winding layer and a second winding layer. A wire winding direction of the first winding layer is opposite to a wire winding direction of the second winding layer so that the wire of the first winding layer and the wire of the second winding layer cross and overlap to each other along part of the bobbin member.

An object is to provide a ferrite composition suitable for an antenna element with a long communication distance in a high-frequency band (for example, 13.56 MHz), a ferrite plate formed of the ferrite composition, a magnetic member for an antenna element formed of the ferrite plate, and an antenna element provided with a member for an antenna element. A ferrite composition, wherein: main components contain, with Fe.sub.2O.sub.3 conversion, 45.0-49.5 mol % of iron oxide, with CuO conversion, 4.0-16.0 mol % of copper oxide, with ZnO conversion, 19.0-25.0 mol % of zinc oxide, a remaining portion is constituted by nickel oxide, an inevitable impurity is removed with respect to the main components, and as accessory components, with TiO.sub.2 conversion, 0.5-2 weight % of titanium oxide, with CoO conversion, 0.35-2 weight % of cobalt oxide are contained.

A mobile platform communication system includes one or more HF antennas disposed in the surface of the mobile platform. The HF antenna may comprise one or more mesh screens. Alternatively, or in addition, the HF antennas may comprise characteristic mode transducers to excite metallic features on the mobile platform skin. The mobile platform skin includes a lightning strike protection layer that is disposed within the mobile platform skin around in internal surface of the antenna such that the antenna does not distend the mobile platform skin and increase drag.

An antenna device or a communication terminal device including the antenna device includes ground conductor, which serves as a plate-shaped conductor and is provided in an inner layer of a circuit board. An antenna coil is mounted so that a first main surface of a magnetic core faces the circuit board. The antenna coil is arranged so that a first conductor portion of a coil conductor is at a position that is closer to the ground conductor than a second conductor portion. The antenna coil is arranged so that the first conductor portion of the coil conductor is positioned in the vicinity of a longitudinal direction end portion of a casing, and the first conductor portion of the coil conductor is bent in a direction toward the ground conductor.

An antenna device or a communication terminal device including the antenna device includes ground conductor, which serves as a plate-shaped conductor and is provided in an inner layer of a circuit board. An antenna coil is mounted so that a first main surface of a magnetic core faces the circuit board. The antenna coil is arranged so that a first conductor portion of a coil conductor is at a position that is closer to the ground conductor than a second conductor portion. The antenna coil is arranged so that the first conductor portion of the coil conductor is positioned in the vicinity of a longitudinal direction end portion of a casing, and the first conductor portion of the coil conductor is bent in a direction toward the ground conductor.

An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may include a ferromagnetic core and an H-field signal winding coupled to the ferromagnetic core. The eLORAN receiver may have an antenna tuning device including a tuning winding surrounding the ferromagnetic core, and a tuning circuit coupled to the tuning winding.

An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may include a ferromagnetic core and an H-field signal winding coupled to the ferromagnetic core. The eLORAN receiver may have an antenna tuning device including a tuning winding surrounding the ferromagnetic core, and a tuning circuit coupled to the tuning winding.

A vehicle door handle for a motor vehicle is described, which includes an integrated transmitting and/or receiving device which comprises an LF antenna and a separately formed NFC antenna. The NFC antenna has a plurality of windings provided on a circuit board. The LF antenna has a plurality of coils wound around a core material formed separately from the circuit board. The NFC antenna encompasses a projection of the LF antenna on the circuit board.

An antenna device includes a power feed coil and a ring-shaped conductor arranged about an axis and a ring-shaped conductor including first and second edge end portions in an axial direction and a cavity inward from the first edge end portion. At least a portion of the cavity overlaps with a coil opening of the power feed coil when seen from the radial direction. The power feed coil causes electric field coupling, magnetic field coupling, and/or electromagnetic field coupling with the cavity. The ring-shaped conductor defines and functions as a booster antenna of the power feed coil. A substantial coil opening defining and functioning as an antenna is larger than that when only the power feed coil is provided, thus facilitating coupling with a communication partner-side antenna coil.