Fig. 1.

a Geometry optimization was performed using a center coil with a ring of coils around it on the outside of the RF coil to minimize coupling. Input parameters to the optimization were the number of coils, the radius of the coil elements (r₁), the radius of the larger ring (r₂), the angle of the outer ring with respect to the main magnetic field direction (α) and the z-offset of the array. b Final result shown with the inner and outer surface of the RF coil. c Realized eight-channel shim array mounted on the RF coil