Textile Characterisation for Wearable Antenna Application using Transmission Line Measurement

This paper presents the conductivity measurement and analysis technique for the conductive textile on low loss and lossy substrates using transmission line measurement. This method is proposed to determine the accurate conductivity properties of the samples based on the transmission parameters, S21 of a two-port transmission line. The experiments were performed on conductive samples; pure copper as a reference and a conductive textile called Shieldit Super. Three samples were fabricated; Copper Pure on Rogers RO5880 as a reference sample, Shieldit Super on R05880 as sample 2 and Shieldit Super on felt fabric as sample 3. Operating at 1.575 GHz, simulation and measurement were carried out to analyse the properties of these three samples. The result shows a close agreement of the measured S21 for the three samples to the simulated value. Result is plotted to observe the conductivity behaviour for all samples and found correlates with the theoretical equation showing the lower the transmission loss, the higher the conductivity, resulting in higher antenna gain performance. Furthermore, a close match is demonstrated for the conductivity results for all fabricated samples to the expected conductivity. Hence, applying the correct technique to measure the material conductivity is imperative, especially for high-frequency applications like antennas.