Publikace

This book gathers, for the first time, an overview of nearly all of the magnetic sensors that exist today. The book is offering the readers a thorough and comprehensive knowledge from basics to state-of-the-art and is therefore suitable for both beginners and experts. From the more common and popular AMR magnetometers and up to the recently developed NV center magnetometers, each chapter is describing a specific type of sensor and providing all the information that is necessary to understand the magnetometer behavior including theoretical background, noise model, materials, electronics, design and fabrication techniques, etc.

This chapter gives a brief overview of parallel fluxgate development, technology and performance. Starting from theoretical background through derivation of fluxgate gating curves, the fluxgate sensor is explained on its typical examples, including sensors with rod-, ring- and race-track core. The effects of geometry, construction and magnetic material treatment on parallel fluxgate noise are discussed in detai. Basic applications of fluxgate magnetometers are given and a quick overview of commercial devices is presented, concluded with recent advances in bulk, miniature, digital and aerospace devices.

The review makes a brief overview of traditional methods of measurement of electric current and shows in more detail relatively new types of current sensors. These include Hall sensors with field concentrators, AMR current sensors, magneto-optical and superconducting current sensors. The influence of the magnetic core properties on the error of the current transformer shows why nanocrystalline materials are so advantageous for this application. Built-in CMOS current sensors are important tools for monitoring the health of integrated circuits. Of special industrial value are current clamps which can be installed without breaking the measured conductor.

Magnetic Sensors: Principles and Applications such as electric current and position measurement

Improving the Accuracy of Magnetic Sensors is possible using various compensation and calibration techniques

Semiconductor magnetic sensors, ferromagnetic magnetoresistors, GMR, SDT, fluxgate and other precise vectorial magnetic sensors: basic principles, properties and applications, mainly in the security area.

This paper presents the design and modeling of a linear eddy current speed sensor with a flat type structure and an air coil configuration. The theory of the eddy current speed sensor is based on utilizing the speed component of the induced currents in a solid moving conductor under stationary or alternating source fields. The stationary part comprises one rectangular excitation coil and two antiserially connected rectangular pick-up coils on the left and right sides of the excitation coil in the direction of the trajectory of the moving part. The moving part is considered firstly as a rectangular conducive ferromagnetic solid iron plate, and secondly as a rectangular aluminum plate. A 3D analytical model using Fourier series is developed to analyze the linear speed sensor in Cartesian coordinates. In addition, the 3D numerical finite element method is used for simulations of the linear speed sensor, and the results are compared with the results for analytical methods. The effects of iron permeability on the speed sensor are calculated for a rectangular ferromagnetic solid iron bar or conductor. The experimental results are presented for a linear speed sensor for a rectangular ferromagnetic solid iron plate and also for a rectangular aluminum plate, at variable speeds. The calculation and the experimental results show that the speed sensor outputs differ completely for solid iron conducive plates and for aluminum conducive plates, due to the different electrical conductivities and magnetic permeabilities.

This paper describes a novel method for calibrating dc-precise magnetometers in the low field range (± 100 μT), which gives acceptable results even in laboratory conditions with significant magnetic interference. By introducing a closely mounted reference magnetometer and a specific calibration procedure, it is possible to compensate for the external magnetic field disturbances caused, e.g., by the local transportation operated with dc power supplies.

This paper considers the possibilities of using digital feedback for precise anisotropic magneto-resistance (AMR) magnetometers using commercial off-the-shelf (COTS) components. This paper presents the full characterization of a real instrument, including its noise, linearity, stability, and power consumption.