Spherical Human Phantoms for Characterization of Implanted Antennas

Implantable antennas cannot be characterized by methods suitable for standard antennas because they are embedded in lossy human tissue, which affects the antenna parameters. In this paper, we consider a canonical spherical human phantom which allows us to characterize the implanted antennas and to determine parameters such as the total radiated power, the power density reaching free space and the antenna gain. For all the mentioned parameters, simple analytical formulas have been derived that enable the calculation of the initial communication link budget between the implanted antenna and an access point located either on the surface body or in the environment out of the body. The results of these expressions have been compared to rigorous models showing excellent agreement and providing valuable insights.