RF Sensors for Monitoring the Electrical Properties of Electrolyte Solutions
Author(s)
Saremi-Yarahmadi, Siavash
Type
Thesis
Abstract
A radio frequency electrical sensor for the qualitative analysis and monitoring of the
electrical properties of electrolyte solutions is designed, simulated and experimentally tested
in this research. This work is based on the use of planar inductors for the detection of a
change in the concentration of ionic species in a liquid sample. At first a literature review on
the physical chemistry of electrolyte solutions is provided. This will include topics on the
conductivity and relaxation properties of electrolytes. This will be followed by a look at
dielectric spectroscopy sensors, electrochemical sensors and inductive sensing devices. The
principles of electrodynamics and constitutive equations are discussed. Based on these, the
principles of operation of the RF electrical sensors are analysed. Two methods of theoretical
analysis of such structures are investigated. These methods are; analytical solution and finite
element computation method. The former offers greater insight into the system’s parameters
whilst the latter offers more information regarding the whole system. Given the qualitative
nature of the sensors under investigation and finite element approach was selected and used
in latter chapters to obtain grater insight into the behaviour of the system.
Planar inductor coils are designed on an FR4 substrate and packaged using PDMS to be used
as sensors in the monitoring of electrical properties of electrolytes. Experimental results on
these sensors are provided and discussed. The effects of solvent, acidity of the solutions, and
environmental factors on the behaviour of the sensors shall be discussed. This is followed by
finite element simulations of the sensor and the effect of various parameters on the overall
behaviour of the sensing device. A transformer apparatus is also constructed and
experimental data are provided for it. An electrolyte is placed on one of the coils of the
transformer and scattering parameters are looked upon for data analysis. The results obtained
using the FE method, is then used to obtain further information about the principle of
operation of the device.
electrical properties of electrolyte solutions is designed, simulated and experimentally tested
in this research. This work is based on the use of planar inductors for the detection of a
change in the concentration of ionic species in a liquid sample. At first a literature review on
the physical chemistry of electrolyte solutions is provided. This will include topics on the
conductivity and relaxation properties of electrolytes. This will be followed by a look at
dielectric spectroscopy sensors, electrochemical sensors and inductive sensing devices. The
principles of electrodynamics and constitutive equations are discussed. Based on these, the
principles of operation of the RF electrical sensors are analysed. Two methods of theoretical
analysis of such structures are investigated. These methods are; analytical solution and finite
element computation method. The former offers greater insight into the system’s parameters
whilst the latter offers more information regarding the whole system. Given the qualitative
nature of the sensors under investigation and finite element approach was selected and used
in latter chapters to obtain grater insight into the behaviour of the system.
Planar inductor coils are designed on an FR4 substrate and packaged using PDMS to be used
as sensors in the monitoring of electrical properties of electrolytes. Experimental results on
these sensors are provided and discussed. The effects of solvent, acidity of the solutions, and
environmental factors on the behaviour of the sensors shall be discussed. This is followed by
finite element simulations of the sensor and the effect of various parameters on the overall
behaviour of the sensing device. A transformer apparatus is also constructed and
experimental data are provided for it. An electrolyte is placed on one of the coils of the
transformer and scattering parameters are looked upon for data analysis. The results obtained
using the FE method, is then used to obtain further information about the principle of
operation of the device.
Date Issued
2012
Date Awarded
2012-12
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Toumazou, Christofer
Fobelets, Kristel
Publisher Department
Electrical and Electronic Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)