RF Conductivity Measurement of Conductive Zell Fabric

• Nguyen, Tien Manh (Department of Electrical & Information Engineering, Seoul National University of Science and Technology) ;
• Chung, Jae-Young (Department of Electrical & Information Engineering, Seoul National University of Science and Technology)
• Accepted : 2015.11.18
• Published : 2016.01.31
• 82 13

Abstract

This study presents a conductivity measurement technique that is applicable at radio frequencies (RF). Of particular interest is the measurement of the RF conductivity of a flexible Zell fabric, which is often used to implement wearable antennas on clothes. First, the transmission coefficient is measured using a planar microstrip ring resonator, where the ring is made of a Zell fabric. Then, the fabric's conductivity is determined by comparing the measured transmission coefficient to a set of simulation data. Specifically, a MATLAB-based root-searching algorithm is used to find the minimum of an error function composed of measured and simulation data. Several error functions have been tested, and the results showed that an error function employing only the magnitude of the transmission coefficient was the best for determining the conductivity. The effectiveness of this technique is verified by the measurement of a known copper foil before characterizing the Zell fabric. The conductivity of the Zell fabric at 2 GHz appears to be within the order of $10^4S/m$, which is lower than the DC conductivity of $5{\times}10^5S/m$.

Keywords

Conductivity;Material Characterization;Ring Resonator;Zell Fabric

Acknowledgement

Supported by : National Research Foundation of Korea (NRF)

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