Research And Simulation Of Electromagnetic Modal For Implantable Devices Energy Delivery Through Volume Conduction

Along with the rapid development of microelectronic technology and signal processing technology, the implantable electronic devices are more and morewidely used in the clinical medicine. Implantable devices are the kind of electronic devices working long time in organism or human body, which are mainly used to measure physiological and chemical parameters change of creature, and they can diagnose and cure some illnesses, especially chronic diseases. Because of implantable characteristic and in order to work steadily and longer in human body, the unit of energy delivery becomes the most important section for implantable devices. Long-term supply of power supply is an important problem. But the battery usually used at present should be replaced through the surgery when it is exhausted. This will aggravate not only the patient's economical burden but also his pains. Magnetic inductive coupling conversion efficiency of power delivery is generally poor due to the energy loss in conductive biological tissue. In order to maintain a sufficient amount of power transfer, a large RF power must be transmitted. This causes RF interference to nearby medical instruments.Based above considerations, a possible plan which can solve the aforementioned power problems of implantable devices is the rechargeable batteries, which can transfer electrical energy in vitro into implantable devices by using volume conduction of biology organism to maintain long-term reliable operation.①The paper introduced electric conduction principle and equivalent circuit of biological tissue, energy transfer technical solution, and it analyzed the structure and electrical properties of human skin.②In order to improve efficiency of delivery electricity, the paper designed different electrode-skin unit increasing transfer efficiency and minishing impedance ratio. First, minishing contact resistance between electrodes and skin; second, optimizeing geometrical shape and arrangement of electrodes.③Energy delivery model of volume conduction was created by COMSOL Multiphysics, electric potential and current density through skin also can be calculated.④According to setup parameters on a common condition, we can calculate energy transfer efficiency and analyze various kinds of results under different situationsBecause of ensuring body safety current, we can finally get the results with a current transmitting efficiency of 20% and the energy delivery efficiency of 4%-9%.The charging system designed in the thesis has resolved the disposable problem of the power supply, and it will have profound significance and wide application prospect.