| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively use a plurality of loop antennas in a reader and writer for performing noncontact communication using the loop antennas. <P>SOLUTION: The reader and writer is provided with resonance frequency varying means C1, D1, C2 and D2 for varying the resonance frequency of each of the plurality of loop antennas, when communication means 1, 2 and 3 perform the noncontact communication by switching a loop antenna to be used for the noncontact communication from among the plurality of loop antennas E1 and E2. Control means 1, 2 and 3 control the resonance frequency varying means so as to make the resonance frequency of the other loop antenna different from the resonance frequency of a loop antenna to be used for the noncontact communication. <P>COPYRIGHT: (C)2007,JPO&INPIT |
