RF transmission power loss variation with abdominal tissues thicknesses for ingestible source

This paper presents the investigation of the variation in RF (radio frequency) transmission power loss at 403 MHz and 923 MHz due to different tissue thicknesses using a layered planar tissue model of skin, subcutaneous fat, abdomen muscle, visceral fat and small intestine. The generalized transmission coefficient is used to calculate the transmission power loss of various tissue thickness combinations that are based on medical findings of human abdomen composition. The calculations show large transmission power loss variations (up to 10 dB). The effect of visceral fat thickness variation is the largest. The results are useful for the design of wireless communications module of an ingestible device, e.g. capsule endoscope.