Re: NEC-LIST: Backscatter from RFID tags - modeling problem

Chip

Problem 1 - how would you define the relationship?

Problem 2 - Until recently communication range has been limited by the power
supply requirements of the tag chip and permitted reader TX power. With
battery assisted backscatter tags, (or newer lower voltage tags) communication
range is limited by the noise at the reader receiver and the tag antenna's
differential reflectivity. I am trying to quantify and model the mechanism in
order to better design tag input circuits.

73
Chris
G4HKP

Chris Turner IEng MIIE
Mobile tel: +44 7812 174133
  ----- Original Message -----
  From: Fractenna_at_aol.com
  To: turner.c_at_virgin.net
  Cc: nec-list_at_gweep.ca
  Sent: Monday, March 03, 2003 12:32 PM
  Subject: Re: NEC-LIST: Backscatter from RFID tags - modeling problem

  You are confusing the effective aperture with the true aperture; that's
  problem number one.

  Analytical estimates of received power are poor predictors of true
  performance in RFID tags, due to the multipath environment and random
  orientation of tags on SKU's, and so on. That's problem 2.

  Finally, is this an academic problem? Tag solutions are now a slam dunk with
  modern technology. Its the straps that are the problem--depending on the
  vendor source.

  73,
  Chip N1IR
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