International Journal on Magnetic Particle Imaging IJMPI
Vol. 12 No. 1 Suppl 1 (2026): Int J Mag Part Imag
https://doi.org/10.18416/IJMPI.2026.2604006

Research Articles, ID 1042

Variable Gain Amplifer for MPS

Main Article Content

Ankit Malhotra (1)Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Lübeck, Germany;2)Institute of Medical Engineering, University of Lübeck, Lübeck, Germany), Pascal Stagge (Fraunhofer IMTE, Fraunhofer Research Institution for Individualized Medical Technology and Engineering IMTE, Lübeck, Germany), Tobias Knopp (1)Fraunhofer IMTE, Fraunhofer Research Institution for Individualized Medical Technology and Engineering IMTE, Lübeck, Germany; 2) Institute for Biomedical Imaging, Technische Universität Hamburg (TUHH), Hamburg, Germany), Thorsten Buzug (1)Fraunhofer IMTE, Fraunhofer Research Institution for Individualized Medical Technology and Engineering IMTE, Lübeck, Germany;2) Institute of Medical Engineering, University of Lübeck, Lübeck, Germany), Mandy Ahlborg (1)Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Lübeck, Germany;2)Institute of Medical Engineering, University of Lübeck, Lübeck, Germany)

Copyright (c) 2026 Ankit Malhotra, Pascal Stagge, Tobias Knopp, Thorsten Buzug, Mandy Ahlborg

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

The magnetic response of superparamagnetic iron oxide nanoparticles (SPIONs) varies significantly during nucleation
and growth, requiring adaptive signal conditioning to avoid saturation and maintain sensitivity. This work
presents the design and experimental characterization of a low-noise variable gain amplifier (VGA) based on the
AD603 for this application. The VGA offers a pin-selectable gain range from ?10 dB to +30 dB, enabling high
gain at early synthesis stages and controlled attenuation at later stages. Performance was evaluated in terms of
transient response, gain, phase behavior, and noise characteristics over a frequency range of 1 kHz to 1 MHz. Measurements
demonstrate stable gain, limited phase variation, and improved noise performance through parallel
amplifier configurations, indicating suitability for low-noise, high-dynamic-range SPIONs measurement systems
such as MPS/MPI devices.

Article Details

References

A. Malhotra, A. von Gladiss, A. Behrends, T. Friedrich, A. Neumann, T. M. Buzug, and K. Lüdtke-Buzug. Tracking the Growth of Superparamagnetic Nanoparticles with an In-Situ Magnetic Particle Spectrometer (INSPECT). Scientific Reports, 2019, doi:10.1038/s41598-019-46882-6

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