Active Versus Passive RFID

• Passive RFID tags have no internal power source; instead, an electrical current in the antenna helps the integrated circuit transmit a response. Transmission range for these read-only tags is relatively limited, to about ten feet. Prices for these tags range from about one-half cent to about five cents, depending on the specific technology. In the military, passive RFID tags generally are used for small containers, items shipped within containers, and individual items.

• Active RFID tags have their own internal power source—usually a battery—and can transmit at higher power levels than passive tags. Tag data also can be rewritten or modified. Active RFID tags remain powered continuously and have a relatively large data capacity—up to 128 programmable. With ranges of about 300 feet, these tags, about the size of a brick, range in price from $1 to $300, depending on the specific technology. The military has been using Active RFID tags for more than 12 years, usually for large items or large pallets.

What is the EPCglobal Gen2 Standard?

The Defense Department has standardized its RFID operations on Electronic Product Code specifications and technology.

EPC — sponsored and managed by EPCglobal Inc., a not-for-profit organization in Lawrenceville, N.J. — is a product identification standard that uniquely identifies objects in the supply chain. The EPCglobal Gen2 protocol ensures interoperability and sets minimum operational expectations for components in the EPCglobal Network, including hardware components.

The Gen2 standard provides:

• Tag selection and identification, offering options for faster inventories
• Dense reader model, allowing for a large number or closely spaced readers with minimal interference and optimized data rate for high noise or high-speed communication
• Sessions, allowing multiple readers to communicate within the same tag population
• Variable data rates, offering link closure in varied environments
• Kill and access passwords, for an extra security layer

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