CSL CS208-3G INTELLIGENT INTEGRATED READER with GPS
USER'S MANUAL, VERSION 1.0.0
Copyright © Convergence Systems Limited, All Rights Reserved
106
Appendix D. RFID Basics
Passive tag RFID technology involves the reader, the antenna and the tag.
The reader sends out energy in the relevant frequency band to the antenna via RF cables, and
the antenna radiates the energy out. This energy impinges on an RFID tag.
The RFID tag consists of an antenna coupled to an RFID IC. This IC converts the AC voltage
it receives at the antenna port to DC voltage that in turn is used to empower the digital circuit
inside.
The digital circuit then turns on and off some components connected to the antenna port,
thereby changing its scattering behavior, in a pre-designed clock rate.
This changing of antenna port parameters then causes a “modulation” of the back-scattered RF
energy.
This modulated back-scattered energy is detected by the reader and the modulation is captured
and analyzed.
