Measuring the attenuation characteristics of biological tissues enabling for low power in vivo RF transmission

In clinical routine there is a need of periodical recording of vital parameters in high risk groups, for example the intraocular pressure. A solution for this could be an intracorporeal sensor using a wireless radio frequency (RF) transmitter. Thereby the risk of an infection is reduced, because a percutaneous connection is not necessary. A limiting factor for some organs is the size of implants. For designing an energy efficient low power RF transmitter, the dielectric parameters of representative biological tissues have to be determined. In this article two methods of measurement are presented, the coaxial probe and transmission line method. With this information about the dielectric parameters a miniaturized RF transmitter was built for proofing tests on phantoms with equal properties like biological tissue.