Noise of a JFET Charge Amplifier for Piezoelectric Sensors

Durdaut, Phillip; Penner, Veronika; Kirchhof, Christine; Quandt, Eckhard; Knöchel, R.; Höft, Michael

doi:10.1109/jsen.2017.2759000

Cited by 41 publications

(32 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Its equivalent circuit is given in Ref. 32 . The PCB is mounted on a 3D-printed holder and encapsulated in a brass cylinder (brass thickness: 2.1 mm) for electrical shielding and mechanical protection.…”

Section: Resultsmentioning

confidence: 99%

Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization

Spetzler

Bald

Durdaut

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Delta-E effect sensors are based on magnetoelectric resonators that detune in a magnetic field due to the delta-E effect of the magnetostrictive material. In recent years, such sensors have shown the potential to detect small amplitude and low-frequency magnetic fields. Yet, they all require external magnetic bias fields for optimal operation, which is highly detrimental to their application. Here, we solve this problem by combining the delta-E effect with exchange biased multilayers and operate the resonator in a low-loss torsion mode. It is comprehensively analyzed experimentally and theoretically using various kinds of models. Due to the exchange bias, no external magnetic bias fields are required, but still low detection limits down to $${{\text{350 pT}} \mathord{\left/ {\vphantom {{\text{350 pT}} {\sqrt {{\text{Hz}}} }}} \right. \kern-\nulldelimiterspace} {\sqrt {{\text{Hz}}} }}$$ 350 pT / Hz at 25 Hz are achieved. The potential of this concept is demonstrated with a new operating scheme that permits simultaneous measurement and localization, which is especially desirable for typical biomedical inverse solution problems. The sensor is localized with a minimum spatial resolution of 1 cm while measuring a low-frequency magnetic test signal that can be well reconstructed. Overall, we demonstrate that this class of magnetic field sensors is a significant step towards first biomedical applications and compact large number sensor arrays.

show abstract

Section: Resultsmentioning

confidence: 99%

Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization

Spetzler

Bald

Durdaut

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…II-F, an electromechanical cantilever exhibits several loss mechanisms that, in the electrical equivalent circuit, are covered by two resistors with the resistances R r + R mag and R ME . In previous studies [24], [25] it has already been shown that both the related thermal-mechanical noise of the resonant structure E d,RrRmag as well as the thermal-electrical noise E d,RME of the dielectric material can accurately be predicted. Adjusting the previously published expressions to the readout structure as depicted in Fig.…”

Section: Phase Noise Analysis a Thermal-mechanical And Thermal-mentioning

confidence: 96%

“…The basic principle is based on a resonant excitation of the sensor with a voltage signal v ex (t) =V ex cos(2πf ex t) with f ex = f res (first bending mode) leading to a magnetically modulated current through the sensor i sensor (t) that, in turn, is transformed into a proportional voltage signal v sensor (t) utilizing a transimpedance amplifier and subsequent phase demodulation. For all measurements a low-noise JFET charge amplifier [25] with a feedback capacitance of C f = 30 pF and a feedback resistance of R f = 5 GΩ is utilized whose transimpedance in the vicinity of f res , i.e. far above the amplifier's lower cutoff frequency (2πR f C f ) −1 ≈ 1 Hz, is given by…”

Section: G Readout Structurementioning

confidence: 99%

“…In previous studies, we focused on thermal noise of magnetoelectric cantilevers in passive mode [24], on the realization and analysis of low-noise preamplifiers for such sensors [25], on noise contributions of the readout electronics [26], [27] and the suppression of the local oscillator's phase noise in active mode magnetoelastic sensor systems [28]. Based on this, in this paper the influence of the sensor's thermal noise on the phase noise is analyzed both metrologically and analytically.…”

Section: Introductionmentioning

confidence: 99%

“…According to previous calculations, the crossover frequency between frequency-dependent and white x is attributed to the influence of the resonator. The slightly different levels of white phase noise floors between the measurements in (a) and (b) are probably due to different states of charge of the battery supplying the amplifier, thus leading to different drain currents in the amplifier's discrete JFET front-end [25].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Fundamental Noise Limits and Sensitivity of Piezoelectrically Driven Magnetoelastic Cantilevers

Durdaut

Rubiola

Friedt

et al. 2020

J. Microelectromech. Syst.

Self Cite

View full text Add to dashboard Cite

Magnetoelastic sensors for the detection of lowfrequency and low-amplitude magnetic fields are in the focus of research for more than 30 years. In order to minimize the limit of detection (LOD) of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. In this contribution, cantilever-type electromechanical and magnetoelastic resonators, respectively, are comprehensively investigated and mathematically described not only with regard to their phase sensitivity but especially to the extent of the sensor-intrinsic phase noise. Both measurements and calculations reveal that the fundamental LOD is limited by additive phase noise due to thermal-mechanical noise of the resonator, i.e. by thermally induced random vibrations of the cantilever, and by thermal-electrical noise of the piezoelectric material. However, due to losses in the magnetic material parametric flicker phase noise arises, limiting the overall performance. In particular, it is shown that the LOD is virtually independent of the magnetic sensitivity but is solely determined by the magnetic losses. Instead of the sensitivity, the magnetic losses, represented by the material's effective complex permeability, should be considered as the most important parameter for the further improvement of such sensors in the future. This implication is not only valid for magnetoelastic cantilevers but also applies to any type of magnetoelastic resonator.

show abstract

A Magnetoelastic Twist on Magnetic Noise: The Connection with Intrinsic Nonlinearities

Spetzler,

McCord

2023

Adv Funct Materials

View full text Add to dashboard Cite

Intrinsic magnetic noise limits the functionality of all magnetic field sensors and related devices using magnetic films as sensing elements. A novel origin of magnetic noise due to ferromagnetic material's magnetostriction is revealed by implementing a comprehensive multi‐level signal‐noise model and thoroughly validating it experimentally on magnetoelectric composite ΔE‐effect sensors. From electrical measurements and operando magnetic domain visualization, magnetic contributions are shown to dominate the noise floor and limit the overall performance of multi‐domain magnetoelastic sensors. The newly introduced noise contribution is correlated with the nonlinearity of the magnetostrictive properties. The effect on sensor output is particularly pronounced in magnetoelastic and magnetoelectric composite devices, but the results generally apply to all sensor devices incorporating magnetic materials. Therefore, the identified magnetic noise source makes a significant contribution to understanding the limitations of magnetic sensors and provides important guidelines for optimizing future magnetic sensors for low detectivity.

show abstract

Noise of a JFET Charge Amplifier for Piezoelectric Sensors

Cited by 41 publications

References 30 publications

Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization

Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization

Fundamental Noise Limits and Sensitivity of Piezoelectrically Driven Magnetoelastic Cantilevers

A Magnetoelastic Twist on Magnetic Noise: The Connection with Intrinsic Nonlinearities

Contact Info

Product

Resources

About