| 摘要 |
<P>PROBLEM TO BE SOLVED: To make possible stable data communications by eliminating a communication unstable area that occurs when a non-contact IC card gets closer to a reader/writer. <P>SOLUTION: An antenna 101 of a non-contact IC card 1 exchanges radio waves with a reader/writer 2. A tuner circuit 102 includes a variable capacitance element, is connected to the antenna 101 and resonates in a frequency of transmitting/receiving signals. A level detection circuit 103 detects an output level of the tuner circuit 102. A tuning control circuit 104 controls a bias current to be supplied to the variable capacitance element of the tuner circuit 12 so that a detection level of the level detection circuit 103 becomes maximum. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
