EM analysis of smart shelf RFID antenna with reconfigurable interrogation zone

This paper presents the design and EM analysis of a near-field RFID antenna for the smart shelf applications where spatially-reconfigurable interrogation zone is required. Antenna operation is based on the EM coupling between the open-ended or shorted microstrip (MS) feed line and parallel planar metal strips printed on top of a dielectric layer. The novelty of the proposed design corresponds to utilizing the RF switches altering the length of meander MS line and thus changing the phase distribution of the radiating antenna elements. Near-field distributions calculated in the planes parallel and normal to the antenna surface illustrate the mechanism of extending an area of strong E-field necessary to activate multiple RFID tags.