Effect of Breathing on UWB Propagation Characteristics for Ingestible and Implantable Devices

Wireless in-body devices are those in which a medical sensor is introduced–implanted or ingested– inside the human body and communicates with a remote node. Some in-body applications demand high data rates, so ultrawideband (UWB) spectrum has been proposed as a good candidate because of its large bandwidth available. Besides, breathing can lead to internal movement of the torso and consequently, of devices installed in this area. Thus, the radio channel performance can be affected by such movement leading to a malfunction of the radio interface of the medical device. This work aims at analyzing the effect of breathing on the propagation channel by means of
in vivo
measurements in living animal models. Continuous wave (CW) measurements have been carried out for five different frequencies in the lower part of the UWB band, and the effects of breathing on the relative received power (module and phase) are analyzed and discussed.