| 摘要 |
<P>PROBLEM TO BE SOLVED: To expand a communication distance with an interrogator by using a Van Atta array antenna capable of acquiring an antenna gain by transmission beam control without complicating a circuit scale. <P>SOLUTION: Three antenna element pairs "101a, 101b ", "102a, 102b" and "103a, 103b" constitute the Van Atta array antenna. When an antenna elements 101a-103b receive interrogation signals radio-transmitted by the interrogator, one part of high-frequency signals applied to transmission lines 109a-111b flow into a rectifier 115 from distribution means 112a-114b, an electromotive force of a predetermined value is generated, and operation power is supplied to a load modulation section 104. In this way, the load modulation section 104 starts an operation of generating a response signal. Since the Van Atta array antenna has a function of automatically directing a transmission beam in the reception direction of a radio wave signal, the generated response signal is transmitted toward the interrogator. <P>COPYRIGHT: (C)2007,JPO&INPIT |
