Polarization-Diversity-Based Rotation Sensing Methodology Using COTS UHF RFID Tags

TL;DR

This paper introduces a novel polarization diversity-based rotation sensing method using COTS UHF RFID tags and SDR technology, enabling rotation speed measurement through phase change analysis of backscatter signals.

Contribution

It presents a new RFID-based rotation sensing approach leveraging polarization diversity and coherent demodulation, validated through experiments.

Findings

Effective rotation speed measurement demonstrated

Theoretical model validated by experimental results

System performance and limitations analyzed

Abstract

Phase-based sensing using ultra-high frequency (UHF) radio-frequency identification (RFID) has, in recent years, yielded numerous additions to the Internet of Things (IoT). This work presents a polarization diversity-based rotation sensing methodology using common-off-the-shelf (COTS) UHF RFID tags identified with a software-defined radio (SDR) UHF RFID reader. The proposed methodology uses the tag-to-reader message after fully coherent demodulation to calculate a difference signal of the backscatter load modulation states. This sequence is then used to compute the rotation speed by evaluating its phase change over time. Experimental results are used to validate the theoretical model and to evaluate the performance and limitations of the proposed system.