Magnetic angular position sensor via a single wheatstone bridge

Precise angular position sensing is essential in diverse fields ranging from manufacturing and navigation to IoT and medical technology. Conventional magnetic angle sensors, such as Hall and magnetoresistive devices, suffer from limitations including a restricted operating field range and the need for multiple devices to achieve full 360° detection. Here, we present a highly simplified angular position sensor that co-integrates anisotropic magnetoresistance (AMR) and the anomalous Nernst effect (ANE) within a single Wheatstone bridge patterned from a single CoFeB layer. Under AC excitation, the first-harmonic longitudinal voltage encodes the AMR response, while Joule-heating–induced thermal gradients generate a second-harmonic transverse ANE voltage. Taking the arctangent of the calibrated ratio provides a continuous 0–360° readout that is inherently insensitive to slow drifts in excitation amplitude. We experimentally demonstrate full-range angle detection with a mean error of 0.51–1.05° over a wide dynamic field window from 100 Oe to 10,000 Oe, covering weak-field robotics through strong-field electromechanical environments. The single-layer, single-bridge architecture suppresses inter-sensor mismatch, minimizes crosstalk, and simplifies trimming, while the harmonic-demodulation scheme affords low noise and compatibility with standard lock-in electronics. A compact analytical model captures the coupled AMR/ANE response and guides bias selection for linearity and robustness against field-magnitude variations. The device is lithography-simple, readily scalable, and amenable to CMOS back-end processing, enabling low-cost wafer-level production. Taken together, these features provide a practical, calibration-light route to high-accuracy, wide-range angular sensing for next-generation encoders, autonomous platforms, and biomedical instruments.

Jiaqi Wang is currently a PhD student focus on the area of spintronic material and  device. He received a master degree from National University of Singapore, Singapore and a bachelor degree from Tianjin University, China.