Design of two-dimensional coils for wireless power transmission to in vivo robotic capsule.

This paper presents a design of two dimensional receiving coils to provide hundreds of milli-watt power via inductive link to in vivo robotic capsules, whose orientation are practically undetermined. The wireless power transmission system consists of a transmitter powered by class E power amplifier, and receiver with 2-dimensional antenna, rectifier, and voltage regulator. Two types of 2-dimensional antennas are designed and evaluated by theoretic and experimental analysis. Experimental results show that the proposed 2-D receiving antenna could deliver the power homogeneously against its orientation, with less than 20% of variation of the possible maximum power.