A comparison of front-end amplifiers for tetrapolar bioimpedance measurements
File(s)
Author(s)
Kassanos, Panagiotis
Seichepine, Florent
Yang, Guang-Zhong
Type
Journal Article
Abstract
Many commercial benchtop impedance analyzers are incapable of acquiring accurate tetrapolar measurements, when large electrode contact impedances are present, as in bioimpedance measurements using electrodes with micrometer-sized features. External front-end amplifiers can help overcome this issue and provide high common-mode rejection ratio (CMRR) and input impedance. Several discrete component-based topologies are proposed in the literature. In this article, these are compared with new alternatives with regard to their performance in measuring known loads in the presence of electrode contact impedance models, to emulate tetrapolar bioimpedance measurements. These models are derived from bipolar impedance measurements taken from the electrodes of a tetrapolar bioimpedance sensor. Comparison with other electrode models used in the literature established that this is a good and challenging model for bioimpedance front-end amplifier evaluation. Among the examined amplifiers, one of the best performances is achieved with one of the proposed topologies based on a custom front-end with no external resistors (AD8066/AD8130). Under the specific testing conditions, it achieved an uncalibrated worst-case absolute measurement deviation of 4.4% magnitude and 4° at 20 Hz, and 2.2% and 7° at 1 MHz accordingly with loads between 10 Ω and 10 kg. Finally, the practical use of the front-end with the impedance analyzer is demonstrated in the characterization of the bioimpedance sensor, in saline solutions of varying conductivities (2.5-20 mS/cm) to obtain its cell constant. This article serves as a guide for evaluating and choosing front-end amplifiers for tetrapolar bioimpedance measurements both with and without impedance analyzers for practical/clinical applications and material/sensor characterization.
Date Issued
2021-01-01
Date Acceptance
2020-07-22
Citation
IEEE Transactions on Instrumentation and Measurement, 2021, 70, pp.1-14
ISSN
0018-9456
Publisher
Institute of Electrical and Electronics Engineers
Start Page
1
End Page
14
Journal / Book Title
IEEE Transactions on Instrumentation and Measurement
Volume
70
Copyright Statement
© The Author(s) 2020. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/
License URL
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000594910700049&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
Science & Technology
Technology
Engineering, Electrical & Electronic
Instruments & Instrumentation
Engineering
Bioimpedance
front-end
impedance analyzer
instrumentation amplifier (IA)
tetrapolar impedance measurement
ELECTRICAL-IMPEDANCE
INSTRUMENTATION AMPLIFIER
NOISE
Publication Status
Published
Article Number
ARTN 200514
Date Publish Online
2020-08-11