| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an antenna controller for a reader-writer, for adjusting the resonance frequency of an antenna used for non-contact communication with a moving object so as to have a frequency which is appropriate for communication. <P>SOLUTION: An automatic adjusting section 12 of a loop antenna A having an automatic adjusting function stores, as a reference value, a power feed voltage level to a loop antenna section 14, in a state where a resonance circuit section 13 is adjusted so that communication of information with the moving object becomes available, measures the power feed voltage level to the antenna when performing communications of information with the moving object; adjusts the resonance circuit section 13 so that the power feed voltage level may be larger when the measured power feed voltage level is smaller than a reference value; and stores (updates) the power feed voltage level in the adjusted state as a reference value afterwards. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
