How we can increase the range of RFID system?
To increase the range you should go to higher frequencies i.e UHF RFid; beacause
the operating zone of passive HF RFID systems (13.56MHz and also <135kHz) is in the ?near field? of the reader transmission antenna, which results in achievable operating distances of approximately the diameter of the transmission antenna. For distances longer than this value the field strength decreases with the third exponent of the distance, which means that the required transmission power increases with the sixth exponent of the distance. Limitations are set by regulations.
Radio Frequency Identification systems operating in the UHF frequency range make use of conventional electromagnetic wave propagation to communicate their data and commands, and also to power the RFID transponders. In EM field, the amount of energy available at any particular point may be expressed as 1/d2 where d is the distance from the transmitter.
Thanks...I also thought like it...but even with normal UHF passive tag can you cover large distance such as 2000meter?
Of course no, the maximum distance of passive UHF tags is about 10m. To cover larger distance you should use battery powered tags.
Even the active RFID may not be able to work with such a long range.