Wireless power transmission system for capsule endoscope

When the capsule endoscope (CE) is travel along the gastrointestinal tract, its position and orientation are always change. In order to continuously transmit enough power to the device, a wireless energy transmission system using Helmholtz transmitting coil and three-dimensional (3-D) receiving coil is introduced in this paper. Helmholtz coil is driven to generate a uniform alternating magnetic field covering whole of the gastrointestinal tract, 3-D coil retrieve enough power regardless of its position and orientation relative to the magnetic field. Up to 180 mW of stable power can be achieved under worst-case geometrical conditions with the outer dimension of the power receiver is Oslash 10 mmtimes10 mm, transmitting power is 16 W and the resonant frequency is 181 kHz. The system is proved to be feasible and practical in power transmitting for CE.