A Simple Diode-Based RF Identification Reader

An RF identification system is used to wirelessly identify, classify, and often retrieve information from remote items. Such systems find applications in tracking mail, classifying stored merchandise in warehouses, remotely collecting tolls from cars and trucks, and even monitoring the TTC cars.

The items to be identified are equipped with low-profile electronic RF "tags". The tags are activated by an RF signal transmitted by the interrogator/reader. Subsequently, the signal transmitted by the tag is received by the reader, thus identifying the presence of the item.

This project focuses on the reader of the RF Identification systems. The reader should be simple and low cost and should be able to differentiate between the signal transmitted by the tag from the signal back scattered from the ambient environment.

any one plz help on this circuit or idea how to.

I know a microwawe EAS tag. It contains a small dipole aerial and a diode as frequency doubler. Another EAS work on 1.95MHz with CW mode, the tag a simple tank circuit. Another method a wobblered signal, the tag also a tank circuit. (3.5...10MHz)
The tags of RFID systems contain a small processor, the reader can identify 2...300 diverse tags (transponders)

hi

sir i will be happy if u send me circuitry or theses that u have or more information plz