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Reference Modulation for Calibrated Measurements of Tag Backscatter
Published
Author(s)
Daniel G. Kuester, David R. Novotny, Jeffrey R. Guerrieri, Randy Direen, Zoya Popovic
Abstract
We present a model and reference backscatter device for calibrating measurements of 860-960 MHz Ultra-High Fre- quency (UHF) tag backscattering. The model relates transmission to and backscattering from the device with a modulation depth calculable from circuit parameters. Unlike the free-space far field approximations, the model is valid in arbitrary stationary linear environments, including the near field of a transmit or measurement antenna, via S-parameters. We use the model to demonstrate an inexpensive reference backscatter device with a common lab switch and loads. Validation measurements on a network analyzer with two expressions for modulation depth agree to within 0.1 dB at 915 MHz. Finally, we present some initial calibrated measurements of backscattered power from a tag at 915 MHz, with estimated uncertainty -0.7 dB to +0.6 dB.
Kuester, D.
, Novotny, D.
, Guerrieri, J.
, Direen, R.
and Popovic, Z.
(2011),
Reference Modulation for Calibrated Measurements of Tag Backscatter, 2011 IEEE International Conference on RFID, Orlando, FL
(Accessed October 10, 2025)