Wireless communication device

• US 9,431,698 B2
• Filed: 04/28/2014
• Issued: 08/30/2016
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Yosui, Kuniaki
• Primary Examiner(s): Kim, Ahshik
• Application Number:
  US14/262,933
• Publication Number:
  US 20140231518A1
• Time in Patent Office: 855 Days
• Field of Search: 235/439, 235/492, 235/451, 235/380, 340/10.1, 340/572.5
• US Class Current: 1/1
• 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 19/07794 the record carrier comprising a booster or auxiliary antenna in addition to the antenna connected directly to the integrated circuit
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• 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: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A wireless communication device includes a resistive-element-including RFIC and an antenna coil. The resistive-element-including RFIC includes an RFIC, a capacitive element, and resistive elements. The resistive elements and a portion of a circuit in the RFIC define a variable impedance circuit. The RFIC controls the impedance of a resistive circuit added to an antenna circuit in accordance with certain IO terminals set as output ports or input ports, thus obtaining a Q value of the antenna circuit in accordance with a communication speed.

Claims

1. A wireless communication device comprising:

a contactless communication IC including a communication terminal configured to transmit/receive a signal and an IO terminal;

an antenna connected to the communication terminal of the contactless communication IC; and

a resistive element connected between the IO terminal and the antenna;

wherein

the IO terminal is settable to define one of an input port and an output port based on an input/output control signal, and the IO terminal has a different impedance when defining an input port and when defining an output port.

2. The wireless communication device according to claim 1, further comprising a circuit that is provided in the contactless communication IC and between the IO terminal and a ground or between the IO terminal and a power line.

3. The wireless communication device according to claim 1, wherein

the communication terminal includes two communication terminals;

a first end and a second end of the antenna are connected to the two communication terminals, respectively;

the IO terminal includes a first IO terminal and a second IO terminal;

the resistive element includes a first resistive element and a second resistive element; and

the first resistive element is connected between the first IO terminal and the first end of the antenna, and the second resistive element is connected between the second IO terminal and the second end of the antenna.

4. The wireless communication device according to claim 3, wherein

the IO terminal further includes a third IO terminal and a fourth IO terminal;

the resistive element further includes a third resistive element that has a resistance value different from the first resistive element and a fourth resistive element that has a resistance value different from the second resistive element; and

the third resistive element is connected between the third IO terminal and the first end of the antenna, and the fourth resistive element is connected between the fourth IO terminal and the second end of the antenna.

5. The wireless communication device according to claim 1, wherein the resistive element and a portion of the contactless communication IC define a variable impedance circuit.

6. The wireless communication device according to claim 1, wherein the resistive element is one of a chip resistor and a resistive pattern.

7. The wireless communication device according to claim 1, further comprising a capacitive element that defines with the antenna an antenna circuit that is an LC parallel resonant circuit.

8. The wireless communication device according to claim 1, wherein the resistive element includes first, second, third and fourth resistive elements, resistance values of the first and second resistive elements being equal, resistance values of the third and fourth resistive elements being equal, and the resistance values of the first and second resistive elements being different from the resistance vales of the third and fourth resistive elements.

9. The wireless communication device according to claim 1, further comprising a casing and two printed-wiring boards provided in the casing, wherein the resistive element and the contactless communication IC are mounted on one of the two printed-wiring boards, the antenna is mounted on another of the two printed-wiring boards, and the two printed-wiring boards are connected to each other.

10. The wireless communication device according to claim 9, wherein the casing includes an upper casing and a lower casing.

11. The wireless communication device according to claim 1, wherein the antenna includes an antenna coil that is a conductor patterned in a rectangular or substantially rectangular spiral.

12. The wireless communication device according to claim 1, further comprising a booster coil antenna configured to magnetically couple with a power feeding coil to define a magnetic field antenna.

13. The wireless communication device according to claim 12, wherein the booster antenna includes coils and capacitive elements.

14. The wireless communication device according to claim 12, wherein the booster antenna includes coil conductors and insulating sheets.

15. The wireless communication device according to claim 1, wherein the antenna is a field emission antenna.

16. A high frequency device comprising the wireless communication device according to claim 1.

17. The high frequency device according to claim 16, wherein the high frequency device is one of an RFID reader/writer and an RFID tag.