Omnidirectional wireless power combination harvest for wireless endoscopy

This paper proposes a power harvest circuit design to combine the received power from three orthogonal receiving coils for the wireless capsule endoscopy. The inductive coupling power harvest circuit consists of three orthogonal coils with parallel LC resonant tank, three rectifiers and an output filtering capacitor. The topology of LC resonant tank and rectifier are discussed. The theoretical expression for the power flow from the transmitter to the receiver is derived, and the power combination mechanism is verified. Simulation results show that the circuit has the characteristics of omnidirectional power receiving. The fluctuation of the received power is in range of 30% (1.5dB) under all possible capsules´ postures.