A radio frequency identification or RFID tag is a device that when used in conjunction with a reader has the ability to track and manage physical assets and living beings, such as animals and employees. RFID tags can be made of different materials and come in various sizes. Additionally, RFID tags have various technical specifications, such as frequency range, data storage capability and power source. These variations allow RFID tags to be used in numerous industries and environments including, retail, automotive, medical, agricultural, construction, oil and gas, transportation, and food service

First, object tags must be placed on each asset or group of assets. Location tags can also be strategically placed to track movement. Once the tags have been placed they generally operate via call and response. For instance, once a passive tag receives a signal or call from a reader, it will respond by sending information back to the reader. This information includes its unique serial number, indicating location, and any other data stored in the tag’s memory. The information gathered and stored in a tag’s memory can be customized to meet the needs of the user. Alternative methods of operation for RFID tags include using them as beacons that automatically send information to a reader. Active tags are often used as beacons, as they are able to ceaselessly broadcast their own signal, as they are independently powered. Active tags can be used to track the minute by minute location of assets, which is ideal for tracking assets that are frequently moved, or that are in areas of constant movement.

A passive tag is powered by a RFID reader, as it does not have a battery. Conversely, an active tag are powered by a battery. Since passive tags do not use batteries, they have a shelf life of up to twenty years. Another advantage is that passive tags come in various sizes, including extra small.  The main disadvantage of passive tags is that they do not have a long reader range. One of the main advantages of using an active tag is that it has a long reader range. Some of the other advantages active tags have included are having a large amount of data storage, the ability to run diagnostics and to independently monitor and regulate. Overall, both passive and active tags have advantages and disadvantages, but ultimately which one is used depends on the intended application of the tag.

The range of a tag varies based on the type and size of the tag and whether the tag is active or passive. For instance, passive tags can be low frequency, high frequency or ultrahigh frequency. The type of frequency impacts a tags range, with low frequency tags having a smaller reader range then ultrahigh frequency range. In addition to the specifications of the tag, the environment in which the tag is used can greatly impact a tags range. For instance, environments that contain a lot of metal or water often require the use of a low frequency tag, as those materials absorb and reflect radio waves impacting their ability to transmit. In these cases, readers must be in a closer proximity to the tag to get a reading. Similarly, the type of reader used can account for variances in range even when using the same type of tag.

Active tags have their own power source, typically a battery. The battery in active tags typically has enough energy to last 3-5 years. On the other hand, passive tags are powered by the reader. When a passive tag is scanned by the reader energy is transmitted via radio waves that are received through the tag’s antenna. The components of the antenna form a magnetic field that powers the tag. The power received by the reader is only enough for the information being stored in the tag to be transferred to the reader. Semi or hybrid tags are often powered by a combination of battery power and reader signals.

There are several types of RFID tags that can be divided into three categories; active, semi-passive and passive.  Within these categories’ tags can be differentiated by several factors. The most common factor is frequency. There are three levels of frequency; low frequency, high frequency and ultrahigh frequency. The level of frequency one uses will depend on the intended application of the tag, as well as the environment and conditions under which the tag will be used. For instance, ultrahigh-frequency tags are better suited to withstand extreme temperatures, making them ideal for use in rugged environments. Similarly, choosing between an active, semi-passive or passive tag depends on the intended use. For instance, active tags have a longer reader range then passive tags, making them ideal for tracking assets over a vast expanse of property.

The components that an RFID tag are made of depends on the level of frequency used by the tag, high versus low, and the type of tag, active versus passive. For instance, a high-frequency passive tag is often made up of a silicon microchip attached to an antenna that is made of copper, silver ink, aluminum or another type of conductive material. The antenna and chip are attached to a layer of polyethylene terephthalate, paper or plastic. Low-frequency passive tags are constructed of the same materials, with the only difference being that the antenna is almost always made of copper. Active tags have all the same components as passive tags, with the addition of a battery and a circuit board. Also, active tags are often encased in plastic.

The price of RFID tags range between a few cents for individual tags to over 100 dollars for bundles. The price varies based on several factors including the type of tag, the number of tags required, the intended application of the tag and whether or not it is purchased with a reader or other sensors. Generally, the more specialized the tag required is the more expensive it will be.