Communication apparatus

摘要

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.

主权项

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.