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

Keywords

RFID, UHF, backscatter, modulation

Citation

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 January 23, 2022)
Created April 14, 2011, Updated February 19, 2017