Patent ID: 7796041
Filing Date: 2010-09-14
Classification: G06K,H01Q

Abstract:
1. A passive radio-frequency identification (RFID) reader operable for creating a relatively uniform near field adjacent a planar surface for reading RFID tags generally above the planar surface, the RFID reader comprising: a plurality of antenna elements distributed in an array underneath the planar surface, and including: a network for distributing electromagnetic energy to the antenna elements such that a current phase of at least one of the perimetric antenna elements is out of phase with and lagging a current phase of the central antenna element; whereby the antenna elements are capable of being turned on at different times for avoiding high far field gain, such that an RFID tag is activated from a corresponding one of the antenna elements that is substantially directly underneath the RFID tag at the time the corresponding antenna element is turned on.