Patent ID: 8773244

Claim:
A communication apparatus comprising: a voltage detection unit for detecting an antenna end voltage of a reader/writer or a non-contact type IC card when non-contact communicating using a load modulation of the non-contact type IC card with respect to a magnetic field signal from the reader/writer; and a characteristics control unit for changing characteristics of an antenna of the reader/writer or the non-contact type IC card when the antenna end voltage detected by the voltage detection unit reaches a predetermined first threshold value, wherein the characteristics control unit only changes the characteristics of the antenna at a timing transmission and reception of data are not being performed, and the characteristics control unit controls transmission and reception of the data to not overlap with a timing the characteristics of the antenna are changed by changing the characteristics of the antenna after a first transmission of the data and a first reception of the data and prior to a second transmission of the data and a second reception of the data, such that the characteristics control unit is configured to control changing the characteristics of the antenna to avoid formation of a non-communicable region while maintaining a communicable distance.