Optimization and Analysis of Tangential Component Orientations in OPM-MEG Sensor Array

Optically pumped magnetometers (OPMs) have brought a transformative advancement to magnetoencephalography (MEG), enabling flexible, noncryogenic, and wearable neuroimaging systems. In particular, the development of triaxial OPM sensors allows for simultaneous measurement of full magnetic field vectors, including both radial and additional tangential components. Previous studies have shown that incorporating tangential components helps enhance the separation between neural signals and external interference, but their optimal configurations remain unclear. This study systematically investigated the impact of tangential component configurations on array sensitivity and the lead field correlation coefficient (R12) in triaxial OPM-MEG sensor arrays, considering tangential component rotations, relative orientations of sensor and source, source depths, and head model types. Based on the above analysis, we proposed an optimization strategy aimed at minimizing R12, referred to as R12-minimization array optimization (RMAO), to explore the optimal configuration of tangential components. The simulation results showed that the proposed method significantly enhanced sensitivity to cortical sources and effectively suppressed external interference, enabling more accurate source localization. This study highlights the critical role of tangential components in improving system performance and provides theoretical foundation and methodological guidance for the design of triaxial OPM-MEG sensor arrays.