Passive RFID card provides advanced sensitivity for enhanced read rates and range. The read range of passive UHF systems can be as long as 12 m, and UHF RFID has a faster data transfer rate than LF or HF. UHF RFID is the most sensitive to interference, but many UHF product manufacturers have found ways of designing tags, antennas, and readers to keep performance high even in difficult environments. The bulk of new RFID projects are using UHF opposed to LF or HF, making UHF the fastest growing segment of the RFID market. The UHF frequency band is regulated by a single global standard called the ECP global Gen2 (ISO 18000-6C) UHF standard. Because transponders do not actively radiate radio waves until they receive a reader signal, they conserve battery life.
Active RFID system typically operate in the ultra-high frequency (UHF) band and offer a range of up to 100 m. In general, active tags are used on large objects, such as rail cars, big reusable containers, and other assets that need to be tracked over long distances. Each beacon’s signal is received by reader antennas that are positioned around the perimeter of the area being monitored, and communicates the tag’s ID information and position. In passive RFID systems, the reader and reader antenna send a radio signal to the tag.
The RFID tags then uses the transmitted signal to power on, and reflect energy back to the reader. Passive RFID systems can operate in the low frequency (LF), high frequency (HF) or ultra-high frequency (UHF) radio bands. Passive tags can be packaged in many different ways, depending on the specific RFID application requirements. The RFID tag can be affixed to an object and used to track and manage inventory, assets, people, etc.
Passive RFID solution are useful for many applications, and are commonly deployed to track goods in the supply chain, to inventory assets in the retail industry, to authenticate products such as pharmaceuticals, and to embed RFID capability in a variety of devices. Passive RFID solution can even be used in warehouses and distribution centers, in spite of its shorter range, by setting up readers at choke points to monitor asset movement. A battery-assisted passive (BAP) has a small battery on board and is activated when in the presence of an RFID reader.
RFID tags contain at least two parts: an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, collecting DC power from the incident reader signal, and other specialized functions; and an antenna for receiving and transmitting the signal. The RFID tag includes either fixed or programmable logic for processing the transmission and sensor data, respectively. The RFID tag receives the message and then responds with its identification and other information.
