Stochastic Analysis of WPT Efficiency due to Location Uncertainty of mm-Sized Deep-Implanted Pacemakers

International audience ; The lossy and heterogeneous nature of the body tissues and the significant wave-impedance contrast as the electromagnetic wave propagates inside the body limits the fundamentally achievable efficiency of far- and midfield wireless charging of deep-body implantable devices. In addition, fluctuations in the implant position cause a further variation in the maximum power transfer efficiency. In this work, the analyzed problem consists of a wireless charged deep-implanted pacemaker considering an electric and a magnetic radiation source and a uniform distribution of pacemaker's positions inside the heart. The results show that the optimal frequency remains the same despite the position fluctuations. However, the efficiency bounds are strongly related to the nature of the source. Therefore, the proposed model and the obtained results serve as a gauge for designing implantable wireless power transfer systems and predicting variations in their efficiency.