| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a reader apparatus for contactless communication that can achieve practical performance at a lower cost in the case that the installed contactless communication reader apparatus and a contactless communication IC possessed by a user are used to manage a plurality of management objects. <P>SOLUTION: A transmission circuit 30 is provided with semiconductor switches comprising transistors Q1, Q3 for turning ON/OFF operations of two systems of amplifiers 33, 35, respectively. Antenna units 50A, 50B each comprising a loop antenna are connected to outputs of the amplifiers 33, 35, and outputs of the amplifiers 33, 35 are provided with detection preventing diodes D1, D2 and semiconductor switches comprising transistors Q2, Q4 for short-circuiting feeding parts and grounds of the antenna units 50A, 50B. A control circuit 20 uses an antenna switching signal SG1 to control turning ON/OFF of the transistors Q1 to Q4 to selectively activate one of the amplifiers and one of the antenna units and to short-circuit the antenna part in non-selection state. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
