In-Body Propagation at ISM and UWB Frequencies for Abdominal Monitoring Applications

This paper presents the results of an in-body propagation study for abdominal implant communication using a bio-matched mini-horn antenna. The wireless signal coverage in the abdomen area at various ISM and UWB frequency bands are measured using electromagnetic simulations with a 3D anatomical voxel model. Power flow analysis is conducted to visualize propagation within the abdominal tissues at several frequencies. As an example, S-Parameters of the channel between a capsule endoscopy pill and an on-body receiver has been studied and channel attenuations at different frequencies are compared. Using the directional bio-matched antenna, it is observed that at 915 MHz the signal coverage in a horizontal plane is sufficient to almost include the whole small intestine. However, the depth of the coverage reduces substantially at higher frequency bands. This comparative analysis can provide some insight on the applicability of these frequencies for various abdominal monitoring applications. It can also provide some information about the required number and placement of the on-body receivers in order to ensure adequate signal reception.