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Reference Modulation for Calibrated Measurements of Tag Backscatter



Daniel G. Kuester, David R. Novotny, Jeffrey R. Guerrieri, Randy Direen, Zoya Popovic


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.
Proceedings Title
2011 IEEE International Conference on RFID
Conference Dates
April 12-14, 2011
Conference Location
Orlando, FL


RFID, UHF, backscatter, modulation


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 July 12, 2024)


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Created April 14, 2011, Updated February 19, 2017