| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To increase a signal receiving level of an antenna of an interrogator. <P>SOLUTION: A common radio wave reflector 13 is faced to the antenna 17 of the interrogator 12 via a responsor 11, disposed in parallel with a dipole antenna 14 of the responsor 11, and separated from the dipole antenna 14 by distance L. The distance L is set at (λg/4±λg/8) or (λg/4(2n+1)±λg/8). Thus, electric field strength of the radio wave from the dipole antenna 14 to the antenna 17 of the interrogator 12 can be increased, a directivity characteristic of the dipole antenna 14 can be narrowed to the direction of the antenna 17 of the interrogator 12. As a result, in the interrogator 12, the receiving level of the antenna 17 is increased, demodulation of the signal becomes easy, and data of demodulation output can be accurately obtained. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
