RFID basics, rfid technical information ,what is rfid, how do rfids work, types of rfid transponder, designing a rfid system,

RFID is short for Radio Frequency Identification Device. Generally a RFID system consists of 2 parts. A Reader,and one or more Transponders, also known as Tags. RFID systems evolved from barcode labels as a means to automatically identify and track products and people. You will be generally familiar with RFID systems as seen in

Access Control.
RFID Readers placed at entrances that require a person to pass their proximity card (RF tag) to be "read' before the access can be made.
Contactless Payment Systems.
RFID tags used to carry payment information. RFIDs are particular suited to electronic Toll collection systems. Tags attached to vehicles, or carried by people transmit payment information to a fixed reader attached to a Toll station. Payments are then routinely deducted from a users account, or information is changed directly on the RFID tag.
Product Tracking and Inventory Control. RFID systems are commonly used to track and record the movement of ordinary items such as library books, clothes, factory pallets, electrical goods and numerous items.

Shown below is a typical RFID system. In every RFID system the transponder Tags contain information. This information can be as little as a single binary bit , or be a large array of bits representing such things as an identity code, personal medical information, or literally any type of information that can be stored in digital binary format.

Shown is a RFID transceiver that communicates with a passive Tag. Passive tags have no power source of their own and instead derive power from the incident electromagnetic field. Commonly the heart of each tag is a microchip. When the Tag enters the generated RF field it is able to draw enough power from the field to access its internal memory and transmit its stored information.
When the transponder Tag draws power in this way the resultant interaction of the RF fields causes the voltage at the transceiver antenna to drop in value. This effect is utilized by the Tag to communicate its information to the reader. The Tag is able to control the amount of power drawn from the field and by doing so it can modulate the voltage sensed at the Transceiver according to the bit pattern it wishes to transmit

Want to design your own reader and need to know about EM4100
compatible Transponders? Click here to learn more about the EM4100
protocol and common encoding schemes used in RFID systems.

APD have a range of RFID products available to those wishing to design and construct their own
RFID systems, We also carry RFID modules for OEM users wanting to quickly incorporate existing products into their own design. Custom designed systems can also be tailor made to suit your Individual requirements. Contact our design department to find out how.

We carry a stock of T5557 RFID transponders. These tags carry 224bits
of Read / Write data, and are suitable for our RFIDREAD-RW reader writer
modules.

See T5557 RFID transponder to learn about reading and writing RFID tags.

Learn more about designing with the EM4095 chip.

As an alternative we also carry the ATMEL U2270B rfid front end chip.
Learn more about designing with the U2270B chip.

There are three types of Transponders. Tags are either Active, Passive, or Semi-passive Transponders. As already mentioned, Passive Transponders have no internal power source. They draw their power from the electromagnetic field generated by the RFID reader. They have no active transmitter and rely on altering the RF field from the transceiver in a way that the reader can detect.
Active transponders have their own transmitters and power source, usually in the form of a small battery. As a result of this they are able to be detected at a greater range than Passive ones. Active Tags remain in a low power "idle" state until they detect the presence of the RF field being sent by the Reader. When the Tag leaves the area of the Reader it again powers down to its idle state to conserve its battery.

Semi-Passive Transponders have their own power source that powers the microchip only. They have no transmitter and as with Passive tags they rely on altering the RF field from the Transceiver to transmit their data.

This low cost proximity keytag is suited for our RFID Reader module as well
as any standard RFID reader that can read EM4100 compatible RFID
transponders. See the specifications for this item.

A critical component of any RFID system is the RFID coil antenna. We keep a stock of RFID coil antennas as they form a core element of our RFID readers. For the convenience of hobbyists and professionals alike you can buy RFID coil antennas direct from our on-line shop.