An H-Shape Magnetic Coupler of the WPT Systems for the Cervical Vertebral Fusion

The adjacent segment degeneration after cervical spine fusion can severely impact the surgical efficacy. Therefore, it is necessary to monitor the stress of the adjacent segments and prevent degenerative diseases caused by excessive pressure. In this paper, a small magnetic coupler with a receiver of only 1.65 cm3 is proposed. And the power can be transferred to the stress transducer in the cervical spine through placing receiver in implants. First, an H-shape magnetic core is proposed to constrain the magnetic field, and the transmitting coil turn is increased to enhance the mutual inductance. Then, the magnetic sheets thickness, magnetic rod diameter and magnetic rod position are optimized by the finite element analysis software. Finally, the proposed structure is compared to existing structure, the mutual inductance is increased by 15 times, and the volume and core loss are basically unchanged. The experiment fully proves the feasibility and superiority of the proposed structure.