A wireless IC device includes a wireless IC chip arranged to process a radio signal, a power-supply circuit board that is connected to the wireless IC chip and that includes a power supply circuit including at least one coil pattern, and a radiation plate arranged to radiate a transmission signal supplied from the power-supply circuit board and/or receiving a reception signal to supply the reception signal to the power-supply circuit board. The radiation plate includes an opening provided in a portion thereof and a slit connected to the opening. When viewed in plan from the direction of the winding axis of the coil pattern, the opening in the radiation plate overlaps with an inner area of the coil pattern and the area of the inner area is approximately the same as that of opening.

A wireless communication device includes an antenna resonance circuit and a wireless IC element. The antenna resonance circuit includes a loop-shaped antenna that performs wireless communication by generating a magnetic field and series inductors connected in series to the loop-shaped antenna. The antenna resonance circuit has a resonant frequency corresponding to a carrier frequency. The wireless IC element is connected to the antenna resonance circuit and processes transmission and reception signals. An inductance value of the series inductors is larger than an inductance value of the loop-shaped antenna, and the series inductors are covered with a magnetic material.

An antenna module includes an antenna element including coil patterns and via conductors coupling together two adjacent two coil patterns. At least one of the coil patterns has a spiral shape, is wound three or more turns parallel or substantially parallel to an outer edge of a principal surface of a multilayer body, includes a first partial pattern including an outer end portion, a second partial pattern extending parallel or substantially parallel with the first partial pattern and being adjacent to the first partial pattern with a first gap provided therebetween, and a third partial pattern extending parallel or substantially parallel with the second partial pattern and being adjacent to the second partial pattern with a second gap provided therebetween, the second gap being smaller than the first gap.

An antenna module includes an antenna element including coil patterns and via conductors coupling together two adjacent two coil patterns. At least one of the coil patterns has a spiral shape, is wound three or more turns parallel or substantially parallel to an outer edge of a principal surface of a multilayer body, includes a first partial pattern including an outer end portion, a second partial pattern extending parallel or substantially parallel with the first partial pattern and being adjacent to the first partial pattern with a first gap provided therebetween, and a third partial pattern extending parallel or substantially parallel with the second partial pattern and being adjacent to the second partial pattern with a second gap provided therebetween, the second gap being smaller than the first gap.

A wireless IC device includes a wireless IC chip arranged to process a radio signal, a power-supply circuit board that is connected to the wireless IC chip and that includes a power supply circuit including at least one coil pattern, and a radiation plate arranged to radiate a transmission signal supplied from the power-supply circuit board and/or receiving a reception signal to supply the reception signal to the power-supply circuit board. The radiation plate includes an opening provided in a portion thereof and a slit connected to the opening. When viewed in plan from the direction of the winding axis of the coil pattern, the opening in the radiation plate overlaps with an inner area of the coil pattern and the area of the inner area is approximately the same as that of opening.

A wireless communication device includes an antenna resonance circuit and a wireless IC element. The antenna resonance circuit includes a loop-shaped antenna that performs wireless communication by generating a magnetic field and series inductors connected in series to the loop-shaped antenna. The antenna resonance circuit has a resonant frequency corresponding to a carrier frequency. The wireless IC element is connected to the antenna resonance circuit and processes transmission and reception signals. An inductance value of the series inductors is larger than an inductance value of the loop-shaped antenna, and the series inductors are covered with a magnetic material.

A compact wireless communication includes a first radiating element and a second radiating element, which define and function as a dipole antenna, a feeder circuit including a wireless IC chip coupled with the first and second radiating elements, and a feeder substrate that is provided with the wireless IC chip. The first radiating element is provided to the feeder substrate. The second radiating element is provided to a substrate other than the feeder substrate.

An antenna coil includes a first conductor pattern defining a first side, a second conductor pattern defining a second side, a third conductor pattern defining a third side, and a fourth conductor pattern defining a fourth side in each turn when viewed from a laminating direction of insulation layers, the first conductor pattern is provided on a first layer, the second conductor pattern is provided on a second layer, which differs from the first layer, and the third conductor pattern and the fourth conductor pattern extend across the first layer and the second layer, and the first through fourth conductor patterns are disposed on the respective insulation layers so that the direction of a line obtained by sequentially connecting, on a turn-by-turn basis, centers of gravity of winding shapes each of which is configured by the conductor patterns defining one turn is slanted relative to the laminating direction of the insulation layers.

An antenna module includes an antenna element including coil patterns and via conductors coupling together two adjacent two coil patterns. At least one of the coil patterns has a spiral shape, is wound three or more turns parallel or substantially parallel to an outer edge of a principal surface of a multilayer body, includes a first partial pattern including an outer end portion, a second partial pattern extending parallel or substantially parallel with the first partial pattern and being adjacent to the first partial pattern with a first gap provided therebetween, and a third partial pattern extending parallel or substantially parallel with the second partial pattern and being adjacent to the second partial pattern with a second gap provided therebetween, the second gap being smaller than the first gap.

A compact wireless communication includes a first radiating element and a second radiating element, which define and function as a dipole antenna, a feeder circuit including a wireless IC chip coupled with the first and second radiating elements, and a feeder substrate that is provided with the wireless IC chip. The first radiating element is provided to the feeder substrate. The second radiating element is provided to a substrate other than the feeder substrate.