| RFID (radio frequency identification) is a form of wireless communication that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency portion of the electromagnetic spectrum to uniquely identify an object, animal or person. Use cases for RFID technology include healthcare, manufacturing, inventory management, shipping, retail sales and home use. Every RFID system consists of three components: a scanning antenna, a transceiver and a transponder. When the scanning antenna and transceiver are combined, they are referred to as an RFID reader or interrogator. The transponder is located in the RFID tag itself. The read range for RFID tags varies based on factors including the type of tag, type of reader, RFID frequency and interference in the surrounding environment or from other RFID tags and readers. Generally speaking, tags that have a stronger power source also have a longer read range. RFID and bar code technology are used in similar ways to track inventory, but three important differences make each one a better choice in certain situations: - RFID tags do not require a direct line of sight to be read.
- Data stored in an RFID tag can be updated in real-time. In contrast, bar code data is read-only and cannot be changed.
- RFID tags require a power source. In contrast, bar codes only require the technology reading the bar code to have a power source.
How RFID tags work An RFID tag consists of a microchip, memory and antenna. The antenna uses radio frequency waves to transmit a signal that activates the tag's transponder. Once activated, the transponder reads or writes data and transmits it back to the antenna for wireless transmission to the reader. The data is used to notify a programmable logic controller in the reader that an action should occur. The action could be as simple as raising an access gate or as complicated as interfacing with a database to carry out a monetary transaction. RFID tags typically hold less than 2,000 KB of data, including a unique identifier/serial number. Tags can be read-only or read-write. Types of RFID tags There are two main types of RFID tags: active RFID and passive RFID. An active RFID tag has its own power source, which is usually a low-power battery. A passive RFID tag, on the other hand, does not require batteries. Instead, it receives its power from the reading antenna, whose electromagnetic wave induces a current in the RFID tag's antenna. Types of RFID systems There are three main types of RFID systems: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Microwave RFID is also available. Frequencies vary greatly by country and region. - Low-frequency RFID systems range from 30 kHz to 500 kHz, though the typical frequency is 125 kHz. LF RFID has short transmission ranges, generally anywhere from a few inches to less than six feet.
- High-frequency RFID systems range from 3 MHz to 30 MHz, with the typical HF frequency being 13.56 MHz. The standard range is anywhere from a few inches to several feet.
- UHF RFID systems range from 300 MHz to 960 MHz, with the typical frequency of 433 MHz and can generally be read from 25-plus feet away.
- Microwave RFID systems run at 2.45 GHz and can be read from more than 30-plus feet away.
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