Images credits: Turck USA; Embedds
RFID transceivers are products which establish RFID reception and transmission on the same integrated circuit. This allows them to reprogram RFID tags.
RFID Transceiver Operation
RFID transceivers function similarly to RFID readers. These devices emit a particular radio frequency signal which is perceived by an RFID tag. If the tag is programmed to a compliant frequency, it will emit a return RF signal which includes the tag's protocol, managing organization, asset description, and serial number. Transceivers are typically cabled to a programmable logic controller (PLC) or computer via an IO module. If the module is programmable, it can be used to provide more comprehensive data to the PLC or computer; the PLC or computer then instructs the RFID transceiver to recode or rewrite the tag if necessary.
Many tags are programmed with protocol, encryption, or a read/write mode which cannot be changed. This prevents the tag from corruption and unauthorized interrogating. Some tags allow these specifications to be changed, in which case the RFID transceiver is capable of rewriting the tag's functionality. Since the frequency of the tag is directly related to the geometry of the antenna, the frequency which it uses cannot be changed, but the depth of its modulation is adjustable. One of the central advantages to an RFID transceiver is the time saved; a module is able to read and rewrite a tag with only one input from the operator.
Image credit: Priority 1 Design
RFID transceivers are common in instances where the RFID tag code needs to be frequently changed. If used in conjunction with encoded software, customized and secure RFID tags can be made. Since the transceiver is capable of reception and transmission, RFID connections which utilize transceivers are better encrypted than those which use RFID readers and tags. The applicable range of the transceiver is often limited to within several inches as an applicative feature, not a design constraint.
The accompanying table represents the most common frequencies used by RFID equipment.
|Band||Range||Data speed||Common uses|
|120—159 kHz (low frequency)||10 cm||Low||Animal identification; factory data collection; auto keys|
|13.56 MHz (high frequency)||10 cm—1 m||Low to moderate||Smart cards; shelf inventories; transactions|
|433 MHz (ultra-high frequency)||1—100 m||Moderate||Defense applications; tracking pallets|
Eurasia: 865—868 MHz (ultra-high frequency)
North America: 902—928 MHz (ultra-high frequency)
|1—12 m||Moderate to high||Inventory; hard-to-read RFID applications|
|2450—6800 MHz (microwave)||1—2 m||High||802.11 WLAN, Bluetooth standards|
|3.1—10 GHz (microwave)||>200 m||High||Road toll accounts|
RFID Transceiver Standards
RFID systems are often regulated by industry standards as a whole, and not by individual components. There is an extensive list of RFID standards available through the IHS Global Standards Store. Some of the more notable standards include:
RFID Transceiver Applications
Applications in which the flexibility of RFID transceivers is useful include:
Inventory and product tracking
Various types of automated manufacturing