Innovative wireless charging system for implantable capsule robots

This article deals with an innovative wireless charging system for an implanted capsule robot. The transmitting coil is given by a combination of a Helmholtz coil and a birdcage coil. This coil configuration generates a magnetic field with all nonzero field components for any location within the human torso. Therefore, a single axis receiving coil wound around a cylindrical shaped ferrite core is able to receive a significant quantity of electrical energy for any capsule orientation and position. Design guidelines are provided and illustrative examples are given. Assuming a capsule of 2 cm length and 1 cm diameter we can transfer at least 1 W to the load with a minimum power transfer efficiency larger than 10% without considering electronic losses. Finally, compliance with electromagnetic field safety limits is assessed by a numerical dosimetric analysis.