3m Innovative Properties Company

Thomas C Mercer

Ronald David Jesme

Edward D Goff

Seth A Lieffort

Jia Hu

William C Egbert

Katherine A Brown

Fay T Salmon

Terry S Nees

Techniques for detecting radio-frequency identification (RFID) tags are disclosed. For example, an exit control system is described that detects unauthorized removal of articles from a protected facility. A series of antennas are setup to produce interrogation corridors located near the exit of the protected area. RFID tags are attached to the articles to be protected. Each tag includes information that uniquely identifies the article to which it is affixed and status information as to whether the articles removal from the facility is authorized. The RF reader outputs RF signals through the antennas to create electromagnetic fields within the interrogation corridors. The reader outputs RF power from a single port to the multiple antennas via a splitter/combiner. In this way, a single RF reader with only one transmitter/receiver port simultaneously interrogates multiple antennas. A variety of techniques are described by which the reader can detect the removal of an unauthorized article.

System for detecting radio-frequency identification tags

Algorithm for RFID security

A durable radio frequency identification tag. A preferred embodiment of the invention provides a durable radio frequency identification tag comprising: a flexible substrate including a first major surface and a second major surface opposite the first major surface; a radio frequency identification antenna attached to the first major surface of the substrate; an integrated circuit attached to the antenna; and a thermoplastic guard attached to the flexible substrate adjacent the integrated circuit. The present invention also provides a method of manufacturing a durable radio frequency identification tag.

Durable radio frequency identification label and methods of manufacturing the same

Growing community of inventors

Maplewood, MN, United States of America

Thomas C Mercer