RFID Transponders

RFID Transponders are combination of a radio and data memory on an integrated circuit chip attached to an antenna.  RFID Transponders have varying "read and write" functionality, power sources, operating frequencies and data capacities.

Read and Write Functionalities: There are three (3) read/write functionalities supported by RFID technology:

Read Only (R) - consisting of a factory-programmed memory with permanently stored information, such as unique serial number.  It can be read multiple times but may not be written to after manufacture.

Write Once Read Many (WORM) - consisting of user-programmable memory with multiple read capability, but can be written to only once after manufacture.

Read/Write (R/W) - consisting of user-programmable memory with multiple read and write capability after manufacture.

RFID Transponders Power Sources: The following power sources apply to RFID Transponders:

Active RFID Transponders are equipped with a battery power source with a finite life span.  They cost more than Passive Transponders but have the benefit of a greater range of signal transmission and in some instances can support processing of data onboard.

Passive Transponders are powered solely by the RF energy emitted from the Interrogator.  They are smaller, lighter, and less expensive than Active Transponders, and have virtually an unlimited life span.  Their range of signal transmission is also shorter, limited by the RF energy emitted from the Interrogator.

RFID Transponder Operating Frequencies: There are three (3) main categories of frequency supported by RFID technology:

• Low Frequency - operates at 125 KHz with typical read range of up to 4" (10 cm)
• High Frequency- operates at 13.56 MHz with typical read range of up to 4' (1.5 m)
• Ultra-High frequency - operates within the 413 MHz through 915 MHz range with typical passive tag read ranges of 10 feet (when adhering to FCC regulations).
• Microwave - operates in frequencies above 2.45 GHz

RFID Transponders: Air Interface Standards: The industry standard for the air interface used by smart labels, ISO 15693, shows the benefits and limitations of this approach. Most smart label and reader suppliers have released or announced compliant products. When all the bugs are out, you'll be able to mix and match components. For example, you might build an access control application around labels using chips from Philips, Intermec handheld computers with RFID readers, customized fixed-mount readers with modules from TAGSYS, and off-the-shelf desktop readers from Texas Instruments.

Once the initial system is installed, the user has a reading infrastructure compatible with any RFID transponder compliant with the ISO 15693 standard. A new application for item tracking might require pallet tags tough enough to survive material handling equipment. The developer of this new application is free to choose any supplier, and as long as the air interface is 15693 compliant, the existing readers will support the new application.