Performance Analysis Of Wireless Capsule Endoscope Antenna In Complex Electromagnetic Environment Of Human Body

In the wireless capsule endoscope(WCE)system,the WCE antenna as the bridge for information and energy transmission in vitro and in vivo,which needs to work in the digestive tract of the human body.The impact of the human tissue must be considered when analyzes the performance of the WCE antenna.But,the age difference of patients with digestive tract diseases are large,using single human model to study the performance of WCE antenna ignores the individual differences among different individuals.Therefore,different human bodies need to be built in order to study the electromagnetic performance of WCE antenna more accurately.In this paper,different human abdomen models are built bases on the partial human model parameters in the CST Voxel Family and combines the knowledge about the physical structure of real human bodies.The electromagnetic performance of WCE antenna in different complex human bodies is simulated and measured.The research results will provide reference for the next design and research of WCE antenna.The main research works are as follows:1.Designing WCE antenna and building simplified human abdominal models.A dual-band flexible dipole antenna is designed that works at ISM(433-434 MHz)and WMTS(1.395-1.4 GHz)band.The antenna has a small size and a relatively wide bandwidth,and as the antenna model of research.According to the partial human model parameters of the CST Voxel Family and combines the basic physiological parameters of real human abdominal,different simplified human abdominal models are established.These models cover different age groups,have detailed organization divisions and reduce the simulation time of the human models,the trade-off between simulation precision and simulation time is realized,the accuracy of performance research for WCE antenna is greatly improved.2.The electromagnetic performance of WCE antenna in different complex human bodies is simulated and analyzed.Frist,the designed dual-band antenna is placed in the gastrointestinal tract organs of simplified abdomen models with different characteristic for electromagnetic simulation,and the simulation results in the same organ of different human bodies are analyzed and compared.The results show that the performance of the antenna changes greatly in different human bodies,the maximum variation of the antenna's return loss coefficient,impedance bandwidth,gain,SAR value and so on,are 19 d B,242 MHz,20.82 d Bi and 160.9 W/kg,respectively.Then,exploring the performance of the antenna in different degree of human obesity.The simulation results show that the degree of human obesity mainly affects the impedance bandwidth of the antenna,and has little effect on the radiation performance of the antenna,the influence of human obesity degree on the SAR is related to human gender.3.Carrying the processing production of the antenna,building measurement setups and measuring the performance of the antenna in different complex human bodies.Frist,different human abdominal measurement models are built by using pork tissues from different parts,and put into the antenna,the related electromagnetic characteristic parameter curves of the antenna are tested,respectively;Then,the ability of the WCE antenna to transmit signals in different human bodies is tested using a dipole antenna operating at 1.4 GHz.Through comparison and analysis,it is found that there exists a little difference between measured and simulation results,which verifies the correctness of the simulation results.Finally,the influence of different gastrointestinal temperature on the performance of the antenna is explored.