RADIO FREQUENCY IC DEVICE

• US 20090160719A1
• Filed: 12/17/2008
• Published: 06/25/2009
• Est. Priority Date: 12/20/2007
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: KATO, Noboru, SASAKI, Jun
• Granted Patent: US 7,990,337 B2
• Time in Patent Office: Days
• US Class Current: 343/742
• 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: H01F 2017/002 Details of via holes for interconnecting the layers
• 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

Abstract

A radio frequency IC device includes a radio frequency IC chip, a feeder circuit substrate, and a radiating plate. The feeder circuit substrate includes a feeder circuit that electrically connects to the radio IC chip and that includes a resonance circuit and/or a matching circuit including inductance elements. The feeder circuit substrate is bonded to the radiating plate, which radiates a transmission signal supplied from the feeder circuit and supplies a received signal to the feeder circuit. The inductance elements are arranged in spiral patterns wound in opposite directions and couple to each other in opposite phases. The radio frequency IC device is able to obtain a radio frequency IC device that is not susceptible to being affected by a usage environment, minimizes variations in radiation characteristics, and can be used in a wide frequency band.

Claims

1. A radio frequency IC device comprising:

a radio frequency IC;

a feeder circuit that is coupled to the radio frequency IC, the feeder circuit is provided on a principal surface provided with input/output terminal electrodes of the radio frequency IC, and includes a resonance circuit including at least two inductance elements and/or a matching circuit including at least two inductance elements; and

a radiating plate arranged to radiate a transmission signal supplied from the feeder circuit and/or supply a received signal to the feeder circuit;

wherein

the feeder circuit is bonded to or placed near the radiating plate; and

the at least two inductance elements include spiral patterns wound in opposite directions.

7. The radio frequency IC device according to claim 1, wherein individual ends of the at least two inductance elements are mutually connected in an electrically conductive manner near a top layer in a laminate and other ends of the at least two inductance elements are coupled to the radio frequency IC.

2. A radio frequency IC device comprising:

a radio frequency IC chip;

a feeder circuit substrate electrically connected to the radio frequency IC chip and provided with a feeder circuit including a resonance circuit including at least two inductance elements and/or a matching circuit including at least two inductance elements; and

a radiating plate arranged to radiate a transmission signal supplied from the feeder circuit and/or supply a received signal to the feeder circuit;

wherein

the feeder circuit substrate is bonded to or placed near the radiating plate; and

the at least two inductance elements include spiral patterns wound in opposite directions.

3. The radio frequency IC device according to claim 2, wherein a resonance frequency of the transmission signal and/or the received signal substantially corresponds to a resonance frequency of the resonance circuit.

4. The radio frequency IC device according to claim 2, wherein the at least two inductance elements are in different positions when the feeder circuit substrate is viewed in a perspective plan view.

5. The radio frequency IC device according to claim 2, wherein each of the at least two inductance elements includes two wiring electrodes adjacent to each other on the same plane.

6. The radio frequency IC device according to claim 2, wherein the feeder circuit substrate includes a laminate and wherein an inside or a surface of a bottom layer of the laminate is provided with flat electrodes, a size of the laminate being about the same as or smaller than that of an outer shape of the at least two inductance elements when the feeder circuit substrate is viewed in a perspective plan view.

8. The radio frequency IC device according to claim 2, wherein

the feeder circuit substrate includes a magnetic substance;

and

the at least two inductance elements are placed in the magnetic substance.

9. The radio frequency IC device according to claim 2, wherein the radiating plate is defined by a loop-shaped electrode having one end and another end and each of the one end and another end couples to one of the at least two inductance elements.

10. The radio frequency IC device according to claim 9, wherein the inductance elements and spiral end portions of the radiating plate that are arranged to couple to each other are wound in the same directions when the feeder circuit is viewed in a perspective plan view.

11. The radio frequency IC device according to claim 9, wherein an inductance value of the loop-shaped electrode is larger than an inductance value of the inductance elements of the feeder circuit.

12. The radio frequency IC device according to claim 9, wherein a magnetic substance is placed inside or on a surface of a loop of the loop-shaped electrode.

13. The radio frequency IC device according to claim 2, wherein the at least two inductance elements connect to the radio frequency IC chip in series.

14. The radio frequency IC device according to claim 2, wherein the at least two inductance elements connect to the radio frequency IC chip in parallel.

15. The radio frequency IC device according to claim 2, wherein inductance values of the at least two inductance elements are substantially the same.

16. The radio frequency IC device according to claim 2, wherein

a plurality of mount electrodes arranged to mount the radio frequency IC chip are placed on a principal surface of the feeder circuit substrate;

and

at least two of the plurality of mount electrodes are electrically connected through the feeder circuit.

17. The radio frequency IC device according to claim 16, wherein the at least two mount electrodes are balanced input/output terminal electrodes.

18. The radio frequency IC device according to claim 2, wherein the feeder circuit includes an auxiliary matching circuit having one end electrically connected to a predetermined position of the feeder circuit and another end that is electrically open.

19. The radio frequency IC device according to claim 2, wherein

a portion of the at least two inductance elements is exposed on a side surface of the feeder circuit substrate;

and

the exposed portion also defines as a radiating plate.

20. The radio frequency IC device according to claim 2, wherein the feeder circuit substrate is a multilayer substrate made of ceramic or resin.

21. The radio frequency IC device according to claim 2, wherein the feeder circuit substrate is a flexible substrate.