Radio communication device
A radio communication device includes a flat radiation element including a loop with a first end and a second end; a feed element including a coil pattern connected to the first end of the loop; and a radio IC element connected to the coil pattern. The coil pattern is disposed near the loop and is wound such that an electric power supply to the coil pattern generates a current flow in the coil pattern and a current flow in the loop in a same direction. The coil pattern and the loop are connected in series and are coupled via a magnetic field.
1. A radio communication device comprising:
a flat radiation element including a loop with a first end and a second end;
a feed element including a first coil pattern connected to the first end of the loop; and
a radio IC element connected to the first coil pattern; wherein
the first coil pattern is disposed adjacent to the loop and is wound such that an electric power supply to the first coil pattern generates a current flow in the first coil pattern and a current flow in the loop in a same direction; and
the coil pattern and the loop are connected in series and are coupled via a magnetic field.
2. The radio communication device according to claim 1 , wherein a winding axis of the first coil pattern extends in a same or substantially a same direction as a central axis of the loop.
3. The radio communication device according to claim 1 , wherein the first coil pattern is located within an area enclosed by the loop in a planar view.
4. The radio communication device according to claim 1 , wherein an inductance value of the first coil pattern is greater than an inductance value generated by the loop.
5. The radio communication device according to claim 1 , wherein the loop is defined by an edge defined by a cut-off portion of the radiation element.
6. The radio communication device according to claim 1 , wherein the radiation element is a grounding conductor provided on a printed wiring board.
7. The radio communication device according to claim 1 , wherein the feed element further includes a capacitor connected in parallel to the radio IC element.
8. The radio communication device according to claim 1 , wherein
the feed element includes, as a base, a laminate body including a plurality of insulating layers located one upon another; and
the first coil pattern has a helical shape and is embedded in the laminate body.
9. The radio communication device according to claim 1 , wherein no conductor pattern that obstructs coupling between the first coil pattern and the loop via a magnetic field is disposed between the first coil pattern and the loop.
10. The radio communication device according to claim 1 , further comprising a second coil pattern connected to the second end of the loop; wherein
the second coil pattern is disposed adjacent the loop and is wound such that an electric power supply to the second coil pattern generates a current flow in the second coil pattern and a current flow in the loop in a same direction.
11. The radio communication device according to claim 10 wherein a winding axis of the second coil pattern extends in a same or substantially a same direction as a central axis of the loop.
12. The radio communication device according to claim 10 wherein a winding axis of the first coil pattern and a winding axis of the second coil pattern are located at a same or substantially a same position or at positions adjacent to each other, in a planar view.
13. The radio communication device according to claim 1 , wherein the feed element includes an LC resonant circuit.
14. The radio communication device according to claim 1 , wherein an induced current flows over almost an entirety of the radiation element and a high-frequency signal is radiated from the entirety of the radiation element.
15. The radio communication device according to claim 1 , further comprising a coil disposed between the second end of the loop and the radiation element.
16. The radio communication device according to claim 1 , wherein an outermost circumference of the coil disposed between the second end of the loop and the radiation element is connected to the second end of the loop and an innermost circumference of the coil disposed between the second end of the loop and the radiation element is connected to the radiation element.
17. The radio communication device according to claim 1 , wherein a slit is provided in the loop.
18. The radio communication device according to claim 17 , wherein the radio communication device is arranged to communicate with a reader-writer of a radio frequency identification system.