Research On High Efficiency Wireless Power Transfer Technology Applied To Implantable Biological Medical Devices

In the field of biomedical research,wireless power transfer has become an inevitable trend in the development of in-body biomedical devices due to its great potential.According to the current research results,the goal of the research is to design a human body wireless power transfer system with high transmission efficiency,and the key problem is how to reduce the high propagation loss caused by electromagnetic wave propagation inside the human body and on the surface.Based on the electrical characteristics of human tissues,this paper analyzes the two main causes of high propagation loss of electromagnetic wave in human tissues,and takes this as the source point of this paper.Through the analysis of each reason,put forward the corresponding technology,and finally propose a system to improve the efficiency of human wireless power transfer.In order to improve the efficiency of human body’s wireless power transfer,this paper has carried out an in-depth study on reducing the propagation loss of electromagnetic wave in human tissues.The main research results of this paper can be summarized as follows: 1.The electrical characteristics of human tissues are introduced in detail,and then the influence of human tissues on electromagnetic wave propagation--internal loss of human tissues and surface reflection of human tissues are studied through theoretical calculation in the case of plane waves.These are the main causes of electromagnetic wave propagation loss,and also the source point of this work.2.Fresnel zone plate is applied to the internal focus of human tissues to solve the problem of internal loss of electromagnetic waves in human tissues.Based on the consideration of the electrical characteristics of human tissues,the design formula is improved and a Fresnel zone plate applied for internal focus of human body is proposed.It can be seen from the experimental measurement results that the designed Fresnel zone plate can improve the transmission efficiency by 389 %,which has a very significant improvement.The experimental measurement is highly consistent with the simulation results,which also verifies the theoretical correctness of the design.On the basis of superior performance,compared with the existing research,the design is simple in structure,convenient in use and low in cost.In addition,the effect of human tissue characteristics on the focusing performance of Fresnel zone plate is discussed,and the performance evaluation method applied to the focusing scene in lossy medium is given also.3.Aiming at the reflection problem of electromagnetic waves on the surface of human tissues,the matching layer technology is applied to the scene of human surface matching.This paper introduces the effect and limitation of the traditional matching technology applied directly to the human body surface matching firstly.On this basis,this paper proposes a new artificial matching layer applied to the human body surface matching--air layer artificial matching layer,which makes the human body surface matching layer technology practical.The experimental results show that the proposed artificial matching layer can improve the transmission efficiency by 245 %.Through the analysis and discussion of simulation and experiment results,the feasibility and practicability of the design are verified.4.Combining the above two technologies,a system is proposed to improve the wireless power transfer efficiency of implantable biological medical devices.Experimental results show that the proposed system can improve the transmission efficiency by 1445 %.In addition,the system is simple in structure and convenient in processing,and has great application potential in biomedical implantation devices.