Analog Front-End Enables Electrical Impedance Spectroscopy System On-Chip for Biomedical Applications

Journal article, 2008

The increasing number of applications of electrical bioimpedance measurement in biomedical application together with the continuous advances in the textile technology applied in the design and development of biopotential electrodes has encouraged several researchers to do the first attempts to develop portable electrical bioimpedance measurement systems and even wearable. The main aim of these systems is mainly home-monitoring. Analog Devices has provided us with the AD5933, a new system-on-chip fully integrated electrical impedance spectrometer which might allow the implementation of minimal size instrumentation for electrical bioimpedance measurements. This system, however, performs a 2-Electrode measurement and thus is not suitable for most of the spectroscopy applications of electrical bioimpedance. In this work we present a relatively simple analog front-end that adapts the AD5933 to a 4-Electrode strategy, allowing its use in biomedical applications. The resulting impedance measurements exhibit a better performance in aspects like load dynamic range and accuracy. These type of minimum-size, AD5933-based bioimpedance measurement systems would lead the researcher to develop and implement light and wearable electrical bioimpedance systems for monitoring applications, a new a huge niche for medical technology development