Development of miniature wireless energy transfer system for implantable pressure sensor

This paper presents a miniature wireless energy transfer system design for implantable pressure sensor used for health monitoring applications. The implantable pressure sensor can be wirelessly powered through strongly coupled magnetic resonance based wireless energy transfer system. The wireless power transfer system has been built up by using a power transmitting circuit which will be placed outside the body and a receiving unit connected to the implantable pressure sensor to be kept inside the body. Experimentally, it has been found that the wireless power transfer from the transmitting coil to the implantable receiving coil depends on the operating frequency, separation distance between the coils and configuration of the coils. It has been found that maximum wireless power transfer occurs from the transmitting unit to the implantable receiving unit at the operating resonant frequency of the system. At the resonant frequency of 562 kHz and optimum load of 40 Ω, a maximum power of 0.186 W and energy transfer efficiency of 26% have been achieved wirelessly with a separation distance of 3 cm between the transmitter and receiver resonators. Electromagnetic simulation has also been carried out using the different forms of transmitting and receiving coils in order to obtain a strong magnetic coupled wireless energy transfer system, which plays an important role in the energy transfer efficiency.