Communication apparatus

• US 9,337,904 B2
• Filed: 07/26/2012
• Issued: 05/10/2016
• Est. Priority Date: 03/06/2012
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Morimoto, Shigeru
• Primary Examiner(s): Lim, Steven
• Assistant Examiner(s): Adnan, Muhammad
• Application Number:
  US14/123,357
• Publication Number:
  US 20140104044A1
• Time in Patent Office: 1,384 Days
• US Class Current: 1/1
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• 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: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

An RFID tag includes an antenna coil configured to transmit and receive a signal through near field communication, a signal processing circuit configured to process the signal transmitted and received by the antenna coil, a capacitive element arranged in series between the antenna coil and the signal processing circuit, and a control unit configured to control the capacity value of the capacitive element. The control unit changes the capacity value of the capacitive element according to whether a voltage is applied from an external power supply.

Claims

1. A communication apparatus comprising:

an antenna configured to transmit and receive a signal through near field communication;

a signal processing circuit configured to process the signal transmitted and received by the antenna;

a capacitive element arranged in series between the antenna and the signal processing circuit;

a voltage monitor unit configured to monitor whether a voltage for operating the communication apparatus supplied by a) an external power supply or b) from another communication apparatus via the antenna and output operation mode information representing whether a voltage is applied from the external power supply;

a storing unit configured to store a reference table that associates a capacity value of the capacitive element with whether a voltage is applied from the external power supply and with a plurality of communication standards; and

a control unit configured to control the capacity value of the capacitive element, wherein

the antenna receives a signal transmitted from another communication apparatus and including communication standard information for specifying a communication standard, the control unit reads out, from the reference table, a capacity value corresponding to the communication standard information included in the received signal and the operation mode information output by the voltage monitor unit and changes a present capacity value of the capacitive element to the read-out capacity value, and

the capacity value read out from the reference table is a value different according to the communication standard information and the operation mode information.

2. The communication apparatus according to claim 1, wherein, when communication is interrupted during data communication or when, although polling communication is successful, data communication does not start, the signal processing circuit carries out a reception operation for a data signal while the control unit changes the capacity value, and the control unit controls the capacitive element with the capacity value at a point when the data signal is received.

3. A communication apparatus comprising:

an antenna configured to transmit and receive a signal through near field communication and including a plurality of antenna coils having inductances different from one another;

a switch configured to switch an antenna coil to anyone of the plurality of antenna coils;

a signal processing circuit configured to process the signal transmitted and received by the antenna;

a capacitive element arranged in series between the antenna and the signal processing circuit;

a voltage monitor unit configured to monitor whether a voltage for operating the communication apparatus is supplied by a) an external power supply or b) from another communication apparatus via the antenna, and output operation mode information representing whether a voltage is applied from an external power supply;

a storing unit configured to store a reference table that associates a capacity value of the capacitive element and the antenna coil with whether a voltage is applied from the external power supply and with a plurality of communication standards; and

a control unit configured to control the capacity value of the capacitive element, wherein

the antenna receives a signal transmitted from another communication apparatus and including communication standard information for specifying a communication standard, the control unit reads out, from the reference table, a capacity value and an antenna coil corresponding to the communication standard information included in the received signal and the operation mode information output by the voltage monitor unit, changes a present capacity value of the capacitive element to the read-out capacity value, and instructs the switch to switch a present antenna coil to the read-out antenna coil, and

the capacity value read out from the reference table is a value different according to the communication standard information and the operation mode information.