Modeling of Tissue Heating by Wireless Power Supply Units of Batteryless Implants

Resumo

The process of heating of surrounding tissues by a wireless power supply unit of batteryless implants with the output power of 500 mW was numerically simulated. The modeled medium consists of four layers: skin, fat, fascia, and muscle. The thicknesses of the layers are 2, 30, 1, and 25 mm, respectively. Heating was estimated for the cases of adiabatic and convective processes, for axially aligned antennas and for the lateral misalignment of the receiving antenna by 25 mm. The power of the heat sources in the first case was 117 mW (transmitting antenna), 6 mW (receiving antenna), and 109 mW (rectifier); in the second case − 210, 5, and 82 mW, respectively. Maximum heating level of the surrounding tissues did not exceed 1.56°С. It was found that planar packaging of the implantable part of the unit (the receiving antenna and the rectifier located in the same plane) reduces heating of the tissue because of better heat dissipation through the skin.