Stoianov Y. Improvement of computational methods for optimal rectenna synthesis for wireless battery charging in an implant

The dissertation is devoted to the solution of the scientific problem, which consists in mathematical modeling of percutaneous transfer of electromagnetic energy and development of computational methods of the rectenna synthesis and control of battery charge of a pacemaker-defibrillator implant, which is for human life support. When powering the implant’s accumulator, it is necessary to control the energy consumption mode, to take into account the variability of biophysical parameters of the channel of energy transfer environment in order to optimize the battery charging process and to use all of its technical resource, which will significantly reduce invasion when using the implant. The methods of rectenna synthesis, in particular its shape, parameters of the radiation pattern are developed. The initial conditions are given, the choice of the criteria for optimizing the shape of the rectenna is substantiated. The method of finding the optimal shape of the rectenna by the non-gradient method is substantiated. The choice of such a non-gradient search method as a genetic algorithm is explained. This method of finding the extreme value of the optimality criterion of the rectenna was chosen because of biomedical constraints (the principle of non-invasiveness), and the interdependence of initial parameters. Optimization of the radiating rectenna’s geometric parameters was performed using the MATLAB and ELCUT environments. Scientific novelty of the obtained results: For the first time the use of eikonal representation of electromagnetic radiation in the optimization of wireless energy transfer through the bioenvironment for charging the battery of the pacemaker-defibrillator implant substantiated. For the first time, the wave function of electromagnetic energy transfer through a layered bioenvironment is determined; a mathematical model of transfer and a method for optimizing battery charge are proposed. It is proposed to use a genetic algorithm for parametric synthesis of the optimal shape of the rectenna, the shape parameters of which are interdependent. For the first time the method and the scheme of remote control of charging of the implant battery is offered. New computational methods of computer simulation and verification of the obtained research results have been developed - mathematical modeling, optimal parametric synthesis of rectenna, and wireless transfer of electromagnetic energy for charging the implant battery. There was performed the analysis of the state and development of mathematical modeling and methods of wireless power transfer through a layered bioenvironment, which allowed further development of the mathematical model and computational methods of percutaneous electricity transfer optimization. A mathematical model of electromagnetic energy transfer through a variable layered bioenvironment has been developed, which allowed to estimate the energy consumed in the transfer channels and to control the battery charge level. New approaches to the construction of pacemakers were made, using problem-oriented tools with knowledge bases to automate the process and predict the impact of unknown factors in maintaining the health of the human body, which allowed to optimize the shape and parameters of the radiating rectenna. The obtained results of experimental researches make it possible to create a rectenna with geometrical parameters necessary to achieve the optimal radiation pattern.