Experimental Investigation of Non-Line-of-Sight Channels in an Intra-Body Network at 2.38 GHz

The characteristics of the intra-body propagation channel between implanted antennas are highly application dependent. Measurements of the forward path gain between identical implant antennas within two multi-layered tissue mimicking liquid phantoms were used to investigate the nature of the intra-body channel at 2.38 GHz. One of the antennas was held in fixed locations in the phantoms and a robotic positioner with millimeter accuracy was used to vary the second antenna's position. The results show that the shortest line-of-sight path is not always dominant and depending on the particular geometry of material layers and their dielectric properties other propagation paths may also be important. This highlights the importance of careful system design in intra-body networks as the link budget between implanted nodes may need to consider alternative propagating paths, depending on the application scenario.