Handheld Bioimpedance Spectrometer for the Total Frequency Range of the  -Dispersion Dhouha Bouchaala Chair of Measurement and Sensor Technology, Chemnitz University of Technology, Germany Dhouha.bouchaala@etit.tu-chemnitz.de Ahmed Fendri National Engineering School of Sfax, Tunisia Ahmedfendri@yahoo.com Olfa Kanoun Chair of Measurement and Sensor Technology, Chemnitz University of Technology, Germany Olfa.kanoun@etit.tu-chemnitz.de Abstract A portable bioimpedance measurement device is useful to provide information non- invasively about patient health in both clinical and home environments. In this work, a handheld bioimpedance spectrometer was developed to realize measurements in the frequency range 5 kHz-1 MHz in order to measure the whole range of the -dispersion which includes the pathological status. The impedance range was chosen from 10 to 10 k for measurements of even low impedances which are important in special medical applications, such as lung edema. 1. Introduction There is still a great need for non-invasive monitoring and detection of pathological changes on a regular basis in clinical and home environments to improve the quality of life for patients. Among many non-invasive techniques such as X-ray, ultrasound, magnetic resonance imaging (MRI), bioimpedance spectroscopy is considered as an attractive diagnostic technique for medical applications. It helps to reduce the healthcare cost and provide reliable repeated instantaneous results. Bioimpedance spectroscopy is based on the injection of a constant current on tissue and the measurement of the resulting voltage at a selected frequency range. The frequency dependence of tissue is known as dispersion. In biological systems, there are three dispersions (alpha, beta, and gamma) from low to high frequencies. The alpha dispersion, from mHz to KHz, relates to the ionic diffusion processes at site of cellular membrane, beta dispersion, from KHz to MHz, is associated with polarization of cellular membranes and gamma dispersion, up to MHz, relates to polarization of water molecules [1]. In this study, we will focus on the beta dispersion since it includes the electrical properties of cells and tissues. The aim of this work is to have a practical, inexpensive and reliable handheld bioimpedance spectrometer used for a wide range of biomedical applications to control patients in clinical and home environments. For reasons of patient safety [2] a maximal AC-current of 0.5 mA and frequency range between 5 kHz and 1 MHz can be applied. The relevant impedance range of pathological status in different diseases is between 10  and 10 k. DOI 10.5162/sensor2013/A8.3 AMA Conferences 2013 - SENSOR 2013, OPTO 2013, IRS 2013 175 2