Investigation of Localizing Precise Human Abdomen Models for Wireless Capsule Endoscopy Antenna Design

To keep safety of the antenna in wireless capsule endoscopy (WCE) to human body and its use range in different groups of people, seven human abdomen models are established where age, tissue thickness, and organ shape have been considered. On the basis of plane wave propagating theory in lossy multilayered media, each model is composed of simulated skin, subcutaneous fat, muscle, visceral fat, and gastrointestinal organ. Different dielectric constants for the biological tissue component are used. A bendable dual-band antenna is designed for the WCE system, conformed to the capsule shell. An L-shaped branch is used to get better impendence matching. Both the ISM band adopted for data transmission and the WMTS band for midfield wireless power transmission are studied. Fresh pork abdominal tissue samples are used as experiment materials, and it is properly kept consistent with the real human abdominal as far as possible. The experimental results show the performance of antenna stable in the ISM (433 MHz) band. The specific absorption ratio value is checked in different models. The results indicate that dielectric parameters varying with age cannot be ignored, and the antenna must be aimed at middle-aged and elderly population with high incidence of gastrointestinal diseases.