Acoustic Wave Devices

Fischerauer, Gerhard; Mauder, A.; Müller, R.

doi:10.1002/9783527620180.ch5

Cited by 10 publications

(11 citation statements)

References 107 publications

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“…Utilizing the inverse piezoelectric effect, a SAW is excited by applying an electrical voltage on an (input) IDT that is patterned on a piezoelectric material. The mechanical wave propagates perpendicular to the direction of the IDT in both directions on the surface of the piezoelectric substrate ([ 5 ], p. 139). For sensing applications the substrate’s surface is frequently coated with an additional layer which reacts to changes of the physical quantity to measure and, in turn, alters the propagating wave in its amplitude and in its velocity.…”

Section: Introductionmentioning

confidence: 99%

Phase Noise of SAW Delay Line Magnetic Field Sensors

Durdaut

Müller

Kittmann

et al. 2021

Sensors

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Surface acoustic wave (SAW) sensors for the detection of magnetic fields are currently being studied scientifically in many ways, especially since both their sensitivity as well as their detectivity could be significantly improved by the utilization of shear horizontal surface acoustic waves, i.e., Love waves, instead of Rayleigh waves. By now, low-frequency limits of detection (LOD) below 100 pT/Hz can be achieved. However, the LOD can only be further improved by gaining a deep understanding of the existing sensor-intrinsic noise sources and their impact on the sensor’s overall performance. This paper reports on a comprehensive study of the inherent noise of SAW delay line magnetic field sensors. In addition to the noise, however, the sensitivity is of importance, since both quantities are equally important for the LOD. Following the necessary explanations of the electrical and magnetic sensor properties, a further focus is on the losses within the sensor, since these are closely linked to the noise. The considered parameters are in particular the ambient magnetic bias field and the input power of the sensor. Depending on the sensor’s operating point, various noise mechanisms contribute to f0 white phase noise, f−1 flicker phase noise, and f−2 random walk of phase. Flicker phase noise due to magnetic hysteresis losses, i.e. random fluctuations of the magnetization, is usually dominant under typical operating conditions. Noise characteristics are related to the overall magnetic and magnetic domain behavior. Both calculations and measurements show that the LOD cannot be further improved by increasing the sensitivity. Instead, the losses occurring in the magnetic material need to be decreased.

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Section: Introductionmentioning

confidence: 99%

Phase Noise of SAW Delay Line Magnetic Field Sensors

Durdaut

Müller

Kittmann

et al. 2021

Sensors

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“…Perturbation formulas for many cases such as mechanical loading, viscoelastic loading, electrical loading, and fluid loading and for many wave types may be found in the literature [8,9].…”

Section: Analytical Approachesmentioning

confidence: 99%

A2.1 - Modeling and Signal Processing Approaches for SAW Chemical Sensors

Fischerauer¹

2011

Proceedings SENSOR 2011

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“…Two SAW device structures are most widely used. A delay line essentially consists of two IDTs placed some distance apart, whereas a resonator has additional reflector gratings to confine the wave energy inside a resonant cavity ([16], p. 141). In most cases, the SAW device is coated with a certain material that interacts with the physical quantity to be measured and, in turn, leads to an alteration of the wave propagating along the substrate’s surface.…”

Section: Introductionmentioning

confidence: 99%

Equivalence of Open-Loop and Closed-Loop Operation of SAW Resonators and Delay Lines

Durdaut

Höft

Friedt

et al. 2019

Sensors

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Surface acoustic wave (SAW) sensors in the form of two-port resonators or delay lines are widely used in various fields of application. The readout of such sensors is achieved by electronic systems operating either in an open-loop or in a closed-loop configuration. The mode of operation of the sensor system is usually chosen based on requirements like, e.g., bandwidth, dynamic range, linearity, costs, and immunity against environmental influences. Because the limit of detection (LOD) at the output of a sensor system is often one of the most important figures of merit, both readout structures, i.e., open-loop and closed-loop systems, are analyzed in terms of the minimum achievable LOD. Based on a comprehensive phase noise analysis of these structures for both resonant sensors and delay line sensors, expressions for the various limits of detection are derived. Under generally valid conditions, the equivalence of open-loop and closed-loop operation is shown for both types of sensors. These results are not only valid for SAW devices, but are also applicable to all kinds of phase-sensitive sensors.

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Acoustic Wave Devices

Cited by 10 publications

References 107 publications

Phase Noise of SAW Delay Line Magnetic Field Sensors

Phase Noise of SAW Delay Line Magnetic Field Sensors

A2.1 - Modeling and Signal Processing Approaches for SAW Chemical Sensors

Equivalence of Open-Loop and Closed-Loop Operation of SAW Resonators and Delay Lines

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