Re: RFID reader design

1) Is it possible to read passive tags at a distance of 6m

That depends on the field strength required to activate
the passive tag. That should be a part of the passive tag
specifications, and is your starting point for the reader design.
Generally, the answer is , yes.

2) Is it possible to build this reader.

Yes. However, you will need the passive tag specs before
you can start the design.


3)What would be the size of reader

I suspect it would be easy to put in a cigar box unless you
need a specific beamwidth for the antenna. It depends upon your
application, and what type of signal processing is needed in the
reader, i.e. does it merely pass the data to and from another
external computer.



4)What would be the power requirement of this reader

It must supply activation energy for the passive tag at the
required distance. That's why you need the tag specifications.
You also need the frequency, since it will be different for all
of the possibles ( 140khz, 13 Mhz, 915 Mhz, 5800 Mhz)


5)Is it possible to detect direction and distance of RFID tag from the
reader

( It depends on the spec requirements. Distance is very difficult and
I would say probably not. Direction can be done using directional
antennae, which rules it out pretty well below 915 Mhz.) A 915
antenna such as the TIRIS antenna is about 5 feet long and 1.5 ft
wide
and will support beamwidths of 25-30 degrees..... approx. ball
park..
5800 directional antenna are about 6 inches in diameter if made
with multiple patches and microstrip................... Don't even
think
about using short pulses for distance --- passive tags can't do that
by a long shot and a reader design would be impractical )

Andy in Eureka , Tex ( retired RFID engineer )

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