Three-dimensional power receiver for in vivo robotic capsules

A three-dimensional wireless power receiver is introduced in this study for in vivo robotic capsules. It is designed to retrieve hundreds of milliwatts of power, regardless of orientation relative to the time-varying magnetic field generated by the external transmitter outside a test animal body. Design issues, such as antenna structure and rectification topology, are discussed, considering limitations of physical space. Various design parameters are implemented and experimented. A selected design is implemented and tested for power variations on rotational positions relative to the transmitter magnetic field. The presented receiver delivers more than 300 mW of power regardless of its orientation. A test capsule is assembled with LED load for in vivo experiments. Visual verification of the light intensity of LED shows that the power-receiving performance of the receiver is not affected inside the animal body.