Project B1 - Sensor Noise Performance and Analogue System Design

This project is aiming at customized analogue signal processing, analogue signal conditioning, as well as sensor conditioning for the different magnetoelectric (ME) sensors which are researched in the CRC. In conjunction with B2, in which it is researched how the analogue signal can be further digitally enhanced with respect to specific applications, it provides the essential link between sensor hardware (A projects) and various applications (B projects). It also plays an important role in the overall measurement system design, which is required for the transfer of ME sensors to application in biomagnetic diagnostics.

An in-depth noise analysis of the different ME sensors provides the basis for the design of sensor systems that have a high signal-to-noise ratio (SNR) and are customized for a specific application. Finding and adjusting the optimal operating point of a sensor is one of the major challenges for designing a robust sensor system. The setting of the operating point includes the generation of a defined magnetic bias field as well as the basic magnetic and electric initialization of the sensor and the sensor system. Consequently, it is necessary to investigate different methods for sensor conditioning. Possible techniques to be investigated range from impedance matching of interdigital transducers (IDTs) in surface acoustic wave (SAW) ME sensors to the creation of advanced and functional printed circuit boards (PCBs) using additive manufacturing techniques, as well as to the adaptation and/or compensation of the Earth's magnetic field with system-intrinsic coil systems on PCB level. It should be emphasized that compensation must be performed at the individual sensor level, especially for individually oriented sensors in sensor arrays. Moreover, it will be researched in close collaboration with B2, if an online calibration during the biomedical measurement could further improve the performance.

In addition, the focus will be on the integration capability of the complete sensor systems using combinations of highly customized application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and system-in-package integration (SIP). This opens new possibilities for the implementation of complex modulation and readout methods for electrically modulated ME sensors (A4, A7) as well as the application of different sensor concepts in large area arrays (B2, B9, 10, B13). As a result, electronics, techniques for sensor conditioning, and readout concepts are expected to be found that provide equivalent performance in terms of SNR and limit of detection (LOD) in a typical clinical environment as under laboratory conditions.

All findings regarding the noise behaviour of the sensitive elements are reported back to Z1 and the A projects, and the B projects will be equipped with the latest measurement systems. All new concepts are investigated and established in close cooperation with project Z2, where it is aimed to establish a systematic toolkit collection of readout circuits that serves as a basis for reproduction and reuse of the customized electronic readout circuits as researched in this and other projects.

Involved Researchers

Person		Role
	Prof. Dr.-Ing. Michael Höft Electrical Engineering Microwave Group	Project lead
	Prof. Dr. Andreas Bahr Electrical Engineering Sensor System Electronics	Project lead
	M.Sc. Johan Arbustini Electrical Engineering Sensor System Electronics	Doctoral researcher
	M.Sc. Henrik Wolframm Electrical Engineering Microwave Group	Doctoral researcher

Role within the Collaborative Research Centre

Project B1 will participate in the focus groups F2 - Modelling, F3 - Comparison of Sensor Concepts, F4 - Magneto­electric Sensors, and F5 - Concepts based on Delta-E Effect. This project provides analogue signal processing and conditioning as the sole project. It complements the hardware of the various kinds of thin-film magnetic field sensors under investigation with the required electronic circuits in order to facilitate their practical application. It therefore provides the indispensable link between bare sensor hardware and subsequent digital signal processing. It also deals with an important part in measurement system design, required for bringing the sensors to application in biomagnetic diagnostics. In particular, the following collaborations with other projects are planned:

Project-related Publications

H. Wolframm, J. Hoffmann, R. Burgardt, E. Elzenheimer, G. Schmidt, M. Höft: PCB Coil Enables In Situ Calibration of Magnetoelectric Sensor Systems, Current Directions in Biomedical Engineering, vol. 9, no. 1, 567-570, 2023.

P. Durdaut, M. Höft: Performance Analysis of Resonantly Driven Piezoelectric Sensors Operating in Amplitude Mode and Phase Mode, Sensors, 23(4), 1899, 2023.

J. Muñoz, J. Arbustini, E. Elzenheimer, M. Höft, A. Bahr: Digital Approaches on Frequency Tuning for Magnetoelectric Sensors, ICECS, 29th IEEE International Conference on Electronics, Circuits & Systems, Glasgow, Scotland, 2022.

H. Wang, J. Arbustini, E. Elzenheimer, V. Schell, M. Höft, E. Quandt, G. Schmidt, H. Heidari, A. Bahr: Study of Chopping Magnetic Flux Modulation on Surface Acoustic Wave Magnetic Sensor, ICECS, 29th IEEE International Conference on Electronics, Circuits & Systems, Glasgow, Scotland, 2022.

J. Arbustini, J. Muñoz, H. Wang, E. Elzenheimer, J. Hoffmann, L. Thormählen, P. Hayes, F. Niekiel, H. Heidari, M. Höft, E. Quandt, G. Schmidt, A. Bahr: MEMS Magnetic Field Source for Frequency Conversion Approaches for ME Sensors, BMT2022 , Joint Annual Conference of the Austrian, German and Swiss Societies for Biomedical Engineering, 2022.

E. Elzenheimer, C. Bald, E. Engelhardt, J. Hoffmann, P. Hayes, J. Arbustini, A. Bahr, E. Quandt, M. Höft, G. Schmidt: Quantitative Evaluation for Magnetoelectric Sensor Systems in Biomagnetic Diagnostics, MDPI Sensors, vol. 22, no. 3, 1018, 2022.

C. Müller, P. Durdaut, R. B. Holländer, A. Kittmann, V. Schell, D. Meyners, M. Höft, E. Quandt, J. McCord: Imaging of Love Waves and Their Interaction with Magnetic Domain Walls in Magnetoelectric Magnetic Field Sensors, Advanced Electronic Materials, 2200033, 2022.

B. Spetzler, P. Wiegand, P. Durdaut, M. Höft, A. Bahr, R. Rieger, F. Faupel: Modeling and Parallel Operation of Exchange-Biased Delta-E Effect Magnetometers for Sensor Arrays, MDPI Sensors, vol. 21, no. 22, 759, 2021.

P. Durdaut, C. Müller, A. Kittmann, V. Schell, A. Bahr, E. Quandt, R. Knöchel, M. Höft, J. McCord: Phase Noise of SAW Delay Line Magnetic Field Sensors, Sensors, vol. 21, issue 16, 5631, 2021.

B. Spetzler, C. Bald, P. Durdaut, J. Reermann, C. Kirchhof, A. Teplyuk, D. Meyners, E. Quandt, M. Höft, G. Schmidt, F. Faupel: Exchange Biased Delta-E Effect Enables the Detection of Low Frequency pT Magnetic Fields with Simultaneous Localization, Scientific Reports 11, Article no. 5269, 2021.

P. Durdaut, E. Rubiola, J.-M. Friedt, C. Müller, B. Spetzler, C. Kirchhof, D. Meyners, E. Quandt, F. Faupel, J. McCord, R. Knöchel, M. Höft: Fundamental Noise Limits and Sensitivity of Piezoelectrically Driven Magnetoelastic Cantilevers, Journal of Microelectromechanical Systems, vol. 29, issue 5, 2020.

B. Spetzler, C. Kirchhof, J. Reermann, P. Durdaut, M. Höft, G. Schmidt, E. Quandt, F. Faupel: Influence of the Quality Factor on the Signal to Noise Ratio of Magnetoelectric Sensors Based on the Delta-E Effect, Applied Physics Letters, vol. 114, issue 18, 183504, 2019.

P. Durdaut, A. Kittmann, A. Bahr, E. Quandt, R. Knöchel, M. Höft: Oscillator Phase Noise Suppression in Surface Acoustic Wave Sensor Systems, IEEE Sensors Journal, vol. 18, no. 12, pp. 4975-4980, 2018.

S. Salzer, V. Röbisch, M. Klug, P. Durdaut, J. McCord, D. Meyners, J. Reermann, M. Höft, R. Knöchel: Noise Limits in Thin-Film Magnetoelectric Sensors With Magnetic Frequency Conversion, IEEE Sensors Journal, vol. 18, no. 2, pp. 596-604, 2018.

A. Kittmann, P. Durdaut, S. Zabel, J. Reermann, J. Schmalz, B. Spetzler, D. Meyners, N. X. Sun, J. McCord, M. Gerken, G. Schmidt, M. Höft, R. Knöchel, F. Faupel, E. Quandt: Wide Band Low Noise Love Wave Magnetic Field Sensor System, Scientific Reports, vol. 8, no. 278, 2018.

P. Durdaut, J. Reermann, S. Zabel, C. Kirchhof, E. Quandt, F. Faupel, G. Schmidt, R. Knöchel, M. Höft: Modeling and Analysis of Noise Sources for Thin-Film Magnetoelectric Sensors Based on the Delta-E Effect, IEEE Transactions on Instrumentation and Measurement, vol. 66, no. 10, pp. 2771-2779, 2017.

P. Durdaut, V. Penner, C. Kirchhof, E. Quandt, R. Knöchel, M. Höft: Noise of a JFET Charge Amplifier for Piezoelectric Sensors, IEEE Sensors Journal, vol. 17, no. 22, pp. 7364-7371 , 2017.

J. Reermann, C. Bald, P. Durdaut, A.Piorra, D. Meyners, E. Quandt, M. Höft, G. Schmidt: Adaptive Mehrkanalige Geräuschkompensation für Magnetoelektrische Sensoren, Proc. DAGA, Kiel, Germany, 2017.

P. Durdaut, S. Salzer, J. Reermann, V. Röbisch, J. McCord, D. Meyners, E. Quandt, G. Schmidt, R. Knöchel, M. Höft: Improved Magnetic Frequency Conversion Approach for Magnetoelectric Sensors, IEEE Sensors Letters, vol. 1, no. 3 , 2017.

P. Durdaut, S. Salzer, J. Reermann, V. Röbisch, P. Hayes, A. Piorra, D. Meyners, E. Quandt, G. Schmidt, R. Knöchel, M. Höft: Thermal-Mechanical Noise in Resonant Thin-Film Magnetoelectric Sensors, IEEE Sensors Journal, vol. 17, no. 8, pp. 2338-2348, 2017.

S. Salzer, P. Durdaut, V. Röbisch, D. Meyners, E. Quandt, M. Höft, R. Knöche: Generalised Magnetic Frequency Conversion for Thin Film Laminate Magnetoelectric Sensors, EEE Sensors Journal, vol. 17, no. 5, pp. 1373-1383, 2017.

J. Reermann, C. Bald, S. Salzer, P. Durdaut, A. Piorra, D. Meyners, E. Quandt, M. Höft, Gerhard Schmidt: Comparison of Reference Sensors for Noise Cancellation of Magnetoelectric Sensors, IEEE Sensors, Orlando, 2016.

E. Yarar, S. Salzer, V. Hrkac, A. Piorra, M. Höft, R. Knöchel, L. Kienle, E. Quandt: Inverse Bilayer Magnetoelectric Thin Film Sensor, Applied Physics Letters, vol. 109, issue 2, 2016.