Design and Implementation of a Magnitude Only Bio-Impedance Analyzer

Date
2018-04-18
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Abstract
The increasing interest in the bio-impedance analysis in various fields has increased the demand for portable and low-cost impedance analyzers that can be used in the field. Simplifying the hardware is crucial to maintaining low-cost and portability, but this is not an easy task due to the need for accurate phase and magnitude measurements. This thesis proposes a new measurement technique that replaces the need to measure the phase by using a software algorithm to extract the phase from the magnitude information. The algorithm which is based on a modified Kramers-Kronig transforms was implemented and tested first using MATLAB, where error and noise analysis on the algorithm were done. Furthermore, the algorithm was written using a python code, and a full Bio-impedance measurement system was proposed to be used for fruit quality control which is receiving increasing attention as an important application of bio-impedance measurements, for being a non-invasive technique. The Final design which was implemented on a printed circuit board (PCB), had a final cost of around $95 CAD and drew a maximum current of around 88mA which satisfies the requirement of a low-cost and low-power device respectively. The device was then tested with passive components and several fruit samples to show that it can effectively monitor fruit samples impedance in the range 100 Ohm-280 kOhm, and a frequency range 1 Hz-10 MHz which is higher than any other work in the literature. The proposed portable bio-impedance analyzers were then used to study the ageing effect of some strawberries samples on their bio-impedance, and the results showed that the device could be used in such an application.
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Keywords
Bio-Impedance, Impedance Spectroscopy, Impedance Analysis, Kramers-Kronig Transform, Impedance Analyzer
Citation
Al-Ali, A. A. (2018). Design and Implementation of a Magnitude Only Bio-Impedance Analyzer (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/31812