Optimizing Corner Geometry of Door Seams in a Magnetic Shielding Room for Enhanced Shielding Effectiveness

Magnetic Shielding Room (MSR) is critically important infrastructure for achieving biomagnetic measurements, providing critical shielding against environmental magnetic noise. Door seams, by disrupting the magnetic circuit, significantly impair the shielding performance inside an MSR. However, there is currently insufficient research on structural refinements for door seams design. To improve the shielding factor (SF) of door seams structures in a MSR against magnetic fields across biomagnetic frequency bands (0.1 Hz–10 kHz), this paper focuses particularly on the geometric shape of door seam corners and the progressive space between each layer of door seams. A 3D finite element model was established and optimized using COMSOL Multiphysics®. Using SF analysis and magnetic field contours, the curvature and gap of door seams corners were optimized, determining the optimal corner radius range (1.6–2.2 mm) and the best distance for the internal seam (2.0–2.4 mm). Simulation results showed that both the saturation radius of rounded corners and the optimal distance of the internal seam significantly enhanced shielding performance, improving SF by 2–4 dB across biomagnetic frequency bands (0.1 Hz-10 kHz). Experimental results demonstrated high agreement with the simulation, validating that these optimizations can create a reduced-noise environment for biomagnetic measurements and facilitate the measurement of lower-amplitude biomagnetic signals.