Smart Sensor Systems: Emerging Technologies and Applications

Chapter 4Dedicated Impedance-Sensor Systems

Gerard Meijer^1,4, Xiujun Li², Blagoy Iliev³, Gheorghe Pop³, Zu-Yao Chang¹, Stoyan Nihtianov^1,4, Zhichao Tan¹, Ali Heidari⁵ and Michiel Pertijs¹

¹Electronic Instrumentation Laboratory, Delft University of Technology, Delft, The Netherlands

²Electronic Instrumentation Laboratory, Exalon, Delft, The Netherlands and Sensytech, Delft, The Netherlands

³Martil Instruments, Heiloo, The Netherlands

⁴SensArt, Delft, The Netherlands

⁵Guilan University, Rasht, Iran

4.1 Introduction

Impedance sensors can be defined as being a set of electrodes which can be used to measure electrical properties of materials or structures. Once these properties are known, it appears that the features of measurements performed with such sensors depend for a large part on the properties of the material or structure to be characterized and only partly on the characteristics of the electrodes. The electrical properties of the sensor in its application can be modeled with passive elements in equivalent electrical circuits. The challenging task for the designer is to make such a sensor system sensitive for the measurands and to obtain immunity for other parameters. In this chapter, we consider impedance sensors to be sensors in a certain measurement environment, and that in the electric model presentation of this setup there is at least one resistive or one reactive component of interest which has to be measured. Impedance sensors can be found in a very wide range of ...