Electromagnetic–Thermal Analysis and Optimization of a Birdcage Coil for Human Brain Magnetic Resonance Imaging

This paper presents the numerical modeling and optimization of low-pass radiofrequency birdcage coil dedicated to human brain imaging at 1.5 T Magnetic Resonance Imaging systems. A three-dimensional numerical model was developed using COMSOL Multiphysics and realistic anatomical geometries of the human head (scalp, skull and brain), constructed in Blender. Electromagnetic simulations evaluated field symmetry, circular polarization, and safety parameters such as specific absorption rate (SAR) and thermal effects. Comparative results between 8-rung and 12-rung coil configuration demonstrated that the 8-rungs design ensures optimal field symmetry and SAR compliance, while the 12-rung design increases local absorption beyond recommended safety thresholds. The numerical simulation results confirm that electromagnetic and thermal analysis of birdcage coils can support performance optimization for improved MRI field distribution while ensuring compliance with safety constraints.