Wireless IC device

• US 8,590,797 B2
• Filed: 08/15/2012
• Issued: 11/26/2013
• Est. Priority Date: 05/21/2008
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru, Ikemoto, Nobuo
• Primary Examiner(s): Lee, Michael G
• Assistant Examiner(s): TARDIF, DAVID P
• Application Number:
  US13/585,866
• Publication Number:
  US 20120305657A1
• Time in Patent Office: 468 Days
• Field of Search: 235/492
• US Class Current: 235/492
• CPC Class Codes: G06K 19/0709 the source being an interrogation field
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07781 the coil being fabricated in a winding process
• CPC Class Codes: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H05K 1/0243 Printed circuits associated with mounted high frequency components
• CPC Class Codes: H05K 2201/10098 Components for radio transmission, e.g. radio frequency identification [RFID] tag, printed or non-printed antennas

Abstract

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.

Claims

1. A wireless integrated circuit device comprising:

a wireless integrated circuit arranged to process a radio signal;

a power-supply circuit connected to the wireless integrated circuit and including a coil pattern; and

a radiation plate arranged to radiate a transmission signal supplied from the power-supply circuit board or to receive a reception signal to supply the reception signal to the power-supply circuit board;

wherein

the radiation plate includes first and second openings arranged adjacent to one another and provided in a portion thereof and a slit connected to the first opening and, when viewed in plan from a direction of a winding axis of the coil pattern, the first opening in the radiation plate overlaps with at least a portion of an inner area of the coil pattern;

the first opening is open to an outside of the radiation plate via the slit; and

the second opening is completely surrounded by portions of the radiation plate so as to be closed to an outside of the radiation plate.

2. The wireless integrated circuit device according to claim 1, wherein, during radiation of the transmission signal, an induced current is excited around the first opening in the radiation plate by a current flowing through the coil pattern and a magnetic field and an electric field caused by the induced current spread over the radiation plate to cause the radiation plate to operate as an electric field antenna.

3. The wireless integrated circuit device according to claim 1, wherein the coil pattern is directly connected to the radiation plate.

4. The wireless integrated circuit device according to claim 1, wherein, when viewed in plan from the direction of the winding axis of the coil pattern, the first opening in the radiation plate substantially entirely overlaps with the inner area of the coil pattern and an area of the first opening is approximately the same as that of the inner area.

5. The wireless integrated circuit device according to claim 1, wherein the wireless integrated circuit is a chip type wireless integrated circuit and is mounted on one main surface of the power-supply circuit board, and the power-supply circuit board is mounted on one of the radiation plate or a support base supporting the radiation plate with another main surface of the power-supply circuit board defining a mounting surface.

6. The wireless integrated circuit device according to claim 5, wherein a mounting electrode that is not directly connected to the power supply circuit is provided on the another main surface of the power-supply circuit board, and the mounting electrode is coupled to a mounting electrode on the radiation plate, which is defined as a portion of the radiation plate via a conductive bond.

7. The wireless integrated circuit device according to claim 6, wherein a main portion of the mounting electrode on the power-supply circuit board is provided in an area other than the inner area of the coil pattern.

8. The wireless integrated circuit device according to claim 1, wherein the power-supply circuit board is defined by a multilayer body including a plurality of layered dielectric layers, and the coil pattern includes a plurality of annular conductors arranged on the plurality of dielectric layers and connected to one another via interlayer conductors in the layered direction of the multilayer body so as to define a helical pattern having the winding axis.

9. The wireless integrated circuit device according to claim 8, wherein each of the plurality of annular conductors provided on the dielectric layers includes a plurality of line conductors that are arranged at predetermined intervals and that are parallel or substantially parallel with each other.

10. The wireless integrated circuit device according to claim 1, wherein the power supply circuit has a resonant frequency and the frequencies of at least one of the transmission signal and the reception signal substantially correspond to the resonant frequency.

11. The wireless integrated circuit device according to claim 1, wherein the radiation plate includes a first electrode including the first opening and the slit and an annular second electrode surrounding the first electrode.

12. The wireless integrated circuit device according to claim 11, wherein the first electrode and the second electrode are integrally provided on one plane.

13. The wireless integrated circuit device according to claim 11, wherein the first electrode is adhered on the second electrode.

14. The wireless integrated circuit device according to claim 11, wherein the radiation plate is made of a metallic material.