Passive RFID tag reader/locator
    2.
    发明申请
    Passive RFID tag reader/locator 审中-公开
    被动RFID标签阅读器/定位器

    公开(公告)号:US20110109442A1

    公开(公告)日:2011-05-12

    申请号:US12591208

    申请日:2009-11-12

    IPC分类号: H04Q5/22

    CPC分类号: G06K7/0008

    摘要: Systems and methods for use in reading and locating passive RFID tags. A reader/locator system sends out a signal with varying frequency. A tag reflects the signal back and the receiver portion of the reader/locator system receives the signal after a certain propagation delay. Since during this propagation delay the transmit frequency has changed, the received signal frequency differs from the one is currently transmitted. The received signal gets mixed with the currently transmitted signal and the resulting beat frequency depends on the frequency variation pattern (which is known) and the signal propagation delay. This beat frequency is directly proportional to the distance between the reader/locator and the RFID tag. The beat frequency can therefore be used to estimate this distance between the reader/locator and the RFID tag. Also provided are methods for determining if an incoming signal is data bearing and a method to obtain a cleaner incoming signal by storing a “carbon footprint” or background clutter and subtracting the carbon footprint from the incoming signal. A novel type of passive RFID tag is also disclosed.

    摘要翻译: 用于读取和定位无源RFID标签的系统和方法。 读取器/定位器系统发送具有不同频率的信号。 标签反映信号,读取器/定位器系统的接收器部分在一定的传播延迟之后接收信号。 由于在该传播延迟期间,发射频率已经改变,所以接收信号频率与当前传输的频率不同。 所接收的信号与当前发送的信号混合,并且所得到的拍频取决于频率变化模式(已知的)和信号传播延迟。 该拍频与读写器与RFID标签之间的距离成正比。 因此,拍频可用于估计读/定位器与RFID标签之间的距离。 还提供了用于确定输入信号是否是数据承载的方法以及通过存储“碳足迹”或背景杂波并从输入信号中减去碳足迹来获得更干净的输入信号的方法。 还公开了一种新型的无源RFID标签。