Miniature sensors are emerging as promising techniques, for example, in diagnostics and environmental control. The aim of this module is to introduce physical principles and electronic realization of miniature sensors exploiting electrodynamic effects. It is sometimes complicated to understand the limitations and possibilities of the individual technologies both in terms of realization and applications. We will in this course get an introduction to several electrodynamic sensor concepts: magnetoresistance (MR) and giant magnetoresistance (GMR), various inductive sensors including search coil and fluxgates, magnetoimpedance (MI) sensors and sensors based on surface plasmon resonance (SPR). Also we will let the sensors compete against each other in order to discover their strength, weaknesses, opportunities and threats. The overall objective of this program is to give you an overview of the state of the art in miniature electrodynamic sensors and to give you hands-on experience in sensor design, output parameter optimization, and sensor applications. The program is divided into five specialist parts which include general characterization of the sensor systems; dc sensing technology based on MR and GMR; ac sensor technology at moderate frequencies based on Faraday’s law of induction (search coil magnetometry, fluxgates and high harmonic generation); ac technology at MHz and microwaves based on giant MI; and optical technologies utilizing SPR.
|Hours of lecture||Hours of discussion||Hours of independent study||Total numbers of hours|
Please note that students are expected to study outside of class for three hours for every hour in class.
The plan is to work through the following topics
- Introduction to sensing systems
- Classification of sensors- physical mechanisms and applications;
- Basic sensing parameters such as sensitivity, drift, offset, full scale;
- Basic laws of electromagnetism;
- Errors of the experimental measurements;
- Noise: electronics, environmental, internal.
- DC sensing technology — magnetoresistance and giant magnetoresistance.
- Generalized Ohm law- combination of Hall and MR effects;
- MR effect, materials and applications;
- GMR effect in nanolayers, mechanism and materials;
- GMR applications in biotechnology, reading heads and MRAM.
- AC sensing technology — low frequencies
- Faraday’s law of induction for sensing applications, search coil magnetometry;
- Non-linear magnetization and generation of high harmonics;
- Fluxgate sensors, principles and materials;
- Applications for low magnetic field detection and embedded sensors.
- AC sensing technology- MHz and GHz
- Skin-effect, the dependence of the skin depth on the magnetic properties;
- High frequency imnpedance and its dependence on the magnetic properties;
- Magnetic sensors based on diagonal and off-diagonal MI effects, technology and materials;
- Applications of MI sensors for extremely low magnetic field detection;
- Applications of MI sensors in smart composites for structural health monitoring.
- Optical sensors based on surface plasmon resonance
- Mechanism of SPR, materials and technology;
- Optimization of SPR multilayer structures;
- Application of SPR in biosensors.
- John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, Second Edition: Electromagnetic, Optical, Radiation, Chemical, and Biomedical Measurement, CRC Press, 2014.
- M. Johnson, Magnetoelectronics. Elsevier Academic Press, 2004
- P. Piprek, Optoelectronic Devices: Advanced simulation and analysis. Springer 2005
- P. Gubin. Magnetic nanoparticles. Wiley, New York, 2009.
Six assignments distributed evenly throughout the term. They include theoretical questions on sensor principles and small sensor design projects.
|Midterm course work||20%|