公开(公告)号：US5825291A

公开(公告)日：1998-10-20

申请号：US827041

申请日：1997-03-25

申请人： Victor Platt ,  Christopher Reinard Paul ,  Thomas A. Nicolette ,  Peter Y. Zhou

发明人： Victor Platt ,  Christopher Reinard Paul ,  Thomas A. Nicolette ,  Peter Y. Zhou

IPC分类号： G08B13/24 ,  H01Q7/04 ,  G08B13/14

CPC分类号： G08B13/2474 ,  H01Q7/04

摘要： An electronic article surveillance system capable of reliable operation at high frequencies such as about 8 MHz, has an arrangement of transmitter and receiver antennas each lying in a flat, horizontal plane in substantial alignment with each other, with the receiver antenna positioned at the floor of a passageway at an interrogation zone and the transmitter antenna positioned overhead. Each antenna takes the form of a pair of parallel-connected, coplanar loops with the transmitter-connected loops being positioned such that electrical current flows around each loop in parallel in the same direction (a ++ configuration) and in the receiver antenna electrical current flows around each loop in parallel in mutually opposite directions (a +- configuration). The antennas are approximately of the same size and overall configuration, and they are positioned in substantial alignment so that the currents induced in the receiver antenna by the field from the transmitter antenna will effectively cancel. Current variations caused by the passage of a target through the interrogation zone will be greater in some of the conductors of the receiver antenna than in others and so can be detected.

摘要翻译： 能够在诸如约8MHz的高频下可靠运行的电子物品监视系统具有发射器和接收器天线的布置，每个发射器和接收器天线彼此基本上对准地位于平坦的水平面中，而接收器天线位于 在询问区的通道和位于顶部的发射机天线。 每个天线采取一对并联连接的共面环路的形式，发射机连接的环路被定位成使得电流沿着相同的方向（a ++配置）并联在每个环路周围，并且在接收机天线中的电流 在相互相反的方向（a +配置）上并联流过每个环路。 天线大致相同的尺寸和总体配置，并且它们被定位成基本对准，使得在接收机天线中由发射机天线的场感应的电流将被有效地消除。 由目标通过询问区引起的电流变化在接收机天线的一些导体中比在其他导体中更大，因此可以检测。