Modeling of Delta-E Effect Magnetic Field Sensors

Equivalent magnetic noise levels at 1 Hz of three GMI samples have been experimentally determined for different excitation conditions related to both dc current and ac excitation amplitude. These three wires or cylindrical-shaped samples are from the exact same alloy composition and obtained from the same fabrication process. The only difference is their diameter which are 80 im, 100 im and 120 im, since this parameter has been identified as an important factor involved in GMI low frequency noise level. Indeed, from the recently proposed model, briefly reminded here, the equivalent magnetic noise level should decrease with the square of the wire diameter. These low frequency equivalent magnetic noise level measurements have been conducted with coherence measurements showing that the main noise source responsible of this noise level is the intrinsic noise of the GMI sensor. Obtained results have then been compared to the expected noise level from the theoretical model, showing a relative good agreement, validating the behavior regarding wire diameter.

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This research presents the analysis of the influence of design parameters on the performance of film bilk acoustic wave resonator (FBAR) working from 15 GHz to 19 GHz. The analysis is done by implementing one-dimensional (1-D) modellings, which are 1-D Mason model and Butterworth Van Dyke (BVD) model. The physical parameters such as piezoelectric materials and its thickness, and size of area affecting the characteristics of the FBAR are analyzed in detail. Zinc oxide (ZnO) and aluminum nitride (AlN) are chosen as the piezoelectric materials. From the analysis, it is found that as the frequency increases, the thickness of the piezoelectric material decreases. Meanwhile, the static capacitance increases as the frequency increases. It is also found that as the area increases, the electrical impedance and static capacitance also increases.

Sensors and measurement systems is an introduction to microsensors for engineering students in the final undergraduate or early graduate level, technicians who wants to know more about the systems they are using, and anybody curious enough to know what microsystems and microsensors can do. The book discusses five families of sensors: - Thermal sensors - Force and pressure sensors- Inertial sensors - Magnetic field sensors- Flow sensorsFor each sensor, theoretical, technology and application aspects are examined. The sensor function is modelled to understand sensitivity, resolution and noise. We ask ourselves: What do we want to measure? What are possible applications? How are the sensor chips made in the cleanroom? How are they mounted and integrated in a system?After reading this book, you should be able to:- Understand important thermal, mechanical, inertial and magnetic sensors- Work with characterization parameters for sensors- Choose sensors for a given application and apply them- Understand micromachining technologies for sensors

As an ultra-sensitivity sensor, a quartz crystal microbalance (QCM) could be used to quantitatively characterize the relation between QCM parameters and the characteristics of viscoelastic films. When a QCM coated with a viscoelastic thin film is in the gas phase, based on the constructive equation of the quartz crystal and ignoring the capacitance effect, the equivalent Butterworth–Van Dyke (BVD) model of the QCM and the explicit expression for its frequency shift are derived. The “extra mass effect” deduced by the complex modulus is also obtained. It is found that the tendency of the BVD model in this work agrees well with that of Voinova’s model, although both are derived in different ways. Meanwhile, it can be seen that the two above-mentioned models exhibit different characteristics when compared with Sauerbrey’s model and Arnau’s model. The BVD model will help analyze the properties of viscoelastic films in the gas phase.

The equivalent magnetic noise spectral density of giant magnetoimpedance (GMI)-based sensors exhibits a low-frequency excess noise inversely proportional to the frequency (1/f noise). In order to enhance the performance and reach the ultimate and intrinsic limit of the magnetometer, it is necessary to investigate the origin of this excess noise. Cross correlation measurements have permitted the demonstration that the excess low-frequency noise arises from the sensor, under defined excitation conditions, particularly the amplitude of the excitation current and the dc bias current. Given that the GMI effect is based on an impedance variation governed by the magnetization direction under an applied external magnetic field, the low-frequency magnetization fluctuations within the GMI wire have been considered to be a possible noise source. The fluctuation-dissipation theorem permits evaluation of the spectral power density of these fluctuations, which is proportional to the imaginary part of the susceptibility, $\chi ^{\prime \prime }$ . The latter may be evaluated by two different methods, based on the measurement of the real part of the wire impedance and on the evaluation of the circumferential hysteresis loop area. The results obtained by both methods are compared and discussed. The values of $\chi ^{\prime \prime }$ thus obtained are then used in order to predict the equivalent magnetic noise level at 1 Hz, and are compared with that measured at 1 Hz. The comparison is conducted for different amplitudes of the dc bias current, and the results obtained indicate that the proposed methods have the potential of predicting the excess noise in GMI sensors.

Reducing equivalent magnetic noise by electrode design and magnetic annealing in Quartz/Metglas magnetoelectric sensors

: A small parallel-plate transmission line (2-1/2 in. high and 12 in. wide) is used to calibrate ground-plane electric and magnetic field sensors. Because this transmission line is relatively small compared to the size of the sensor being tested, some uncertainties have existed. The acquisition and subsequent use of a transverse electromagnetic (TEM) cell have increased the accuracy of calibrating these electric and magnetic field sensors because the TEM cell has the capability of creating a well-known plane-wave electromagnetic field within the TEM cell. This document reports the newly established calibration procedure to be followed when the TEM is used to calibrate ground- plane-version electric and magnetic field sensors. Also included is a complete description of the field sensors tested and the derivation of the calibration procedure. Keywords: Sensor calibration; Electric field sensor; Magnetic field sensor.

Equivalent circuit models for unloaded piezoelectric vibrators are presented. The new circuit model includes terms which take into account the dielectric and piezoelectric loss as well as the mechanical loss found in the standard Van Dyke's model. The new model contains two branches, the motional branch and the static branch, like the Van Dyke's model. However there is no resistance element in the motional branch and the losses (mechanical, dielectric, piezoelectric) associated with the vibrator are represented as imaginary components of the remaining circuit elements (C/sub 0/, C/sub 1/, L/sub 1/). The model produced impedance curves that very closely matched the impedance calculated by using the equation derived from vibration theory and data from lead zirconate titanate and PVDF copolymer samples. The calculation of the circuit parameters C/sub 0/, C/sub 1/, and L/sub 1/ from the complex elastic, dielectric and piezoelectric material constants is straightforward and the model accurately represents the impedance spectra about the fundamental resonance even when the mechanical Q of the resonator is as low as 2. Conversely, If the circuit parameters are known, the material constants including losses can be derived by straightforward calculations without the loss of any information.

A magnetic field sensor consisting of a surface acoustic wave (SAW) generator and a cantilever beam with NdFeB permanent magnets are developed. The working principle of this magnetic sensor relies on the center frequency shift of the SAW device under the magnetic field as a consequence of the torque-effect-induced deformation of the cantilever, which changes the stress on the piezoelectric LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and the spacing between the interdigital transducers (IDTs). Compared with other magnetic sensors based on acoustic resonance, the performance of our proposed sensor is greatly enhanced due to the structural design by incorporating the magnetic torque effect. High sensitivity of 1277.69 kHz/Oe and a large percentage change in frequency of 5.177% are achieved in this magnetic sensor near a resonant frequency of 848 MHz. The proposed magnetic sensor based on SAW and torque effect exhibits great potential for applications in magnetic field detection.

A magnetic field sensor is presented which is based on the inverse Wiedemann effect (IWE) on amorphous wires. The external magnetic DC field to be detected changes the time symmetry of the output voltage induced in a pick-up coil, creating even harmonics. Measurement results show important advantages in sensitivity and working frequencies mainly due to the core's geometry. The sensor has outstanding sensitivity for magnetic fields below 0.02 mT, as well as a low working frequency and current intensity. >

This article introduces a novel plasmonic magnetic field sensor (MFS) that utilizes a Metal-Insulator-Metal (MIM) waveguide configuration with a W-shaped cavity filled with magnetic fluid (MF). The MFS's unique design combines the advantages of plasmonic sensing, offering a promising solution for the detection of magnetic field strength. It operates based on the inherent properties of surface plasmon polaritons and the magneto-optical properties of MF, resulting in a shift in resonant wavelength. The performance of the proposed MFS has been investigated through numerical calculation employing the finite element method (FEM). Remarkably, the MFS exhibits a maximum magnetic field sensitivity of 49.11 pm/Oe, covering a detection range from 33 Oe to 200 Oe. The recorded figure of merit (FOM) and Q-factor of the MFS are 18.39 and 18.4 respectively, attesting to its high performance and reliability. This innovation has the potential to revolutionize fields such as navigation, medical diagnostics, and robotics technologies by seamlessly integrating optical sensing into traditional devices. The proposed sensor's excellent performance, compact size, and cost-effectiveness position it as a promising technology for widespread adoption, contributing to advancements in magnetic field sensing across scientific, industrial, and technological domains.

A study of magnetic field measurements of electronics devices has been conducted. Magnetic field measurement is done by two methods, that is Arduino based measurement by using magnetic field sensor with C + language. Other measurements use magnetic sensors and Logger Lite software with Labquest Mini interface. In Arduino measurements, the measurement results are made in units of Tesla. ADC Arduino has 10 bits. The resolution of this magnetic sensor is 1.6 gauss/volt. Display data in the form of sensor read voltage is changed in milli Tesla (mT) by dividing the data reading voltage sensor value with a value of slop 0.160 mT and intercept -0.32 mT. Measurement results are compared with measurements using magnetic field sensors and free Logger Lite software. The results found that there was no significant difference on measurement data between Arduino and logger lite. The larger difference is 0.032, a result of Servo measurement and the lower is 0.002 mT, result of Coil with 1 Ampere measurement. The conclusion of these two methods is the measurement of the magnetic field using Arduino is recommended to be used.

In this paper, we introduce a revolutionary interaction framework that is based on the idea of around device interaction. The proposed method constitutes a touch-less data entry system that is based on the interaction between the magnetic fields around a device and a magnet. The magnetic field that surrounds the device is generated by a magnetic sensor (compass) that is embedded in the new generation of mobile phones. The movements of a permanent magnet in front of the device deforms the sensor's original magnetic field pattern whereby we can constitute a new means of communication between the user and the device. Thus, the magnetic field encompassing the device plays the role of a communication channel and encodes the hand-movement patterns of the user into temporal changes of the sensor's magnetic field. In the back-end of the communication, an engine samples the momentary status of the field during a trial and recognizes the user's pattern by matching it against some pre-recorded templates. The proposed method has been tested in a variety of applications (such as micro-interaction, handwriting recognition, user authentication, etc) and concluded in very promising results.

The magnetic field of Earth, Be, is an intriguing topic in the introductory physics curriculum that engages students’ curiosity and inspires numerous speculations about the nature of this phenomenon. There are several methods for measuring Earth’s magnetic field. Probably, the most widespread and visual method of measuring the field in student lab experiments utilizes a tangent galvanometer. Recently, PASCO scientific suggested to use a magnetic field sensor for this goal, in a procedure where a magnetic field sensor combined with a rotary motion sensor is rotated in a 2-D plane containing the magnetic field vector of Earth. In this case, the magnetic field detected by the magnetic field sensor is a component of the magnetic field vector oriented relative to the direction of the magnetic field sensor probe (radial component of magnetic field). This means that the detected magnetic field considered as a function of the angle of rotation of the sensor will be a sinusoidal function. The amplitude of this function is the magnitude of Earth’s magnetic field. In conducting this experiment, initially the sensor is set to zero by placing it in a Zero Gauss Chamber (mu-metal). The equipment setup of the experiment is depicted in the figure shown in Ref. 9. The described experiment requires the use of a dip needle that is a compass pivoted to move in the plane containing the magnetic field vector of Earth. The dip needle shows the dip angle θ (inclination) that Earth’s magnetic field makes with the horizontal. Besides the previously mentioned devices, this experiment requires the use of an aluminum table clamp, adjustable angle clamp, and angle indicator to ensure proper alignment of the rotary motion sensor in a 2D plane containing the magnetic field vector.