EAS Anti-shoplifting Tag

Since they were first marketed in 1966, antishoplifting tags have become so popular that a billion dollars worth of them were manufactured last year to combat thefts that cost retailers 15 billion dollars a year. Using the tags is one of the most effective deterrents available to store owners. Some tags are hard tags or buttons that are attached to merchandise with pins that can be removed only with a special tool; these tags can be reused repeatedly by the merchant. Other tags look like thick, plastic labels; these are not removed from the merchandise during purchase, but they are electronically deactivated so the product can be taken from the store without activating the alarm. Tags of this type are disposable, although they can be reactivated if the purchased item is returned to the store for exchange or refund.

Within the retail industry, the devices are generally known as security tags or Electronic Article Surveillance (EAS) tags. The technology favored for modern tags involves a set of gates that transmits pulses of a low-range radio frequency. Inside each security tag is a resonator, a device that picks up the transmitted signal and repeats it. The set of gates also contains a receiver that is progranmned to recognize whether it is detecting the target signal during the time gaps between the pulses being broadcast by the gates. Sensing a signal during these intervals indicates the presence of a signal being resonated (rebroadcast) by a security tag in the detection zone. When this occurs, the gates sound an alarm; in some systems, the alarm sound is accompanied by a flashing light.

Disposable, label-style security tags are becoming increasingly popular, particularly when the tags are inserted inside the product or its packaging by the manufacturer. This “source tagging” makes the devices less accessible for tampering or premature removal, as well as eliminating the time spent by retail clerks to attach and remove tags.

EAS Hard tags are formed from durable plastic, and the pin used to attach the tag to the product is made of nickel-plated steel. Disposable tags are formed from more flexible plastic, such as polypropylene. Conductive and non-conductive components of the resonator units include such materials as copper, aluminum, cellulose acetate, acrylic, and polyester.

The following description applies generically to reusable hard tags; details may vary among manufacturers. Disposable security tags are manufactured in a similar manner, except that the resonator is sealed inside a flexible plastic envelope, which may be backed with adhesive.