Highly Sensitive GMI Sensor with Wide Dynamic Range Based on Single-Coil Feedback
Seiji Idachi, Tsuyoshi Uchiyama · Journal of Magnetics · 2024
Giant magnetoimpedance (GMI) sensors are typically used for the detection of weak biomagnetic fields. Existing methods for increasing the linear operating range of giant magnetoimpedance (GMI) sensors require additional feedback coils, increase the size of the GMI sensors. In this study, we extended the dynamic range of a pulse excitation-driven GMI sensor by implementing single-coil feedback to an off-diagonal GMI sensor. We employed a h igh- pass f ilter to effectively separate the sensor"s output waveform from the feedback current. Investigating the optimum feedback gain for high sensitivity and dynamic range allowed us to achieve a dynamic range of 130 dB without increasing the noise floor.