Residual impedance effect on emulated bioimpedance measurements using Keysight E4990A precision impedance analyzer

摘要

The passive electrical properties of a biological tissue, often referred to as the tissue bioimpedance, can be measured using a range of commercially available impedance analyzers. Using commercially available equipment reduces the time to collect measurements and does not require investigators to have the necessary expertise to design and fabricate custom equipment. However, the test configurations to collect the bioimpedance during tissue measurements introduces residual impedances resulting from the tissue/electrode interface and electrode placements. The presence of these residual impedances can influence the accuracy of the collected measurements and impact the range of frequencies that can be reliably measured. This work presents a systematic study of the effect of residual impedances ranging from 1 Omega to 10 k Omega on the accuracy of impedance measurements representative of bioimpedance applications using a Keysight E4990A impedance analyzer. Additionally, experimental data from measurements of a 2R-C model that emulates a biological tissue impedance displays <1% and <5% relative differences for the resistance and reactance, respectively, from 10 kHz to 100 kHz in configurations with residual impedances <1 k Omega and for residual impedances emulating the tissue/electrode interface. (C) 2018 Elsevier Ltd. All rights reserved.