Analysis of Specific Absorption Rate and Current Density in an Energy Transmission System for a Wireless Capsule Endoscope

This paper reports on the electromagnetic influences on the analysis of biological tissue surrounding a prototype energy transmission system for a wireless capsule endoscope. Specific absorption rate (SAR) and current density were analyzed by electromagnetic simulator in a model consisting of primary coil and a human trunk including the skin, fat, muscle, small intestine, blood and backbone. SAR and current density as a function of frequency and output power were analyzed. The SAR was below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). At the same time, the results for current density show that the influence on biological tissue was lowest in the 300-400 kHz range, indicating that it was possible to transmit energy safely up to 100 mW.