Advances in Radio Science www.adv-radio-sci.net 1684-9965 1684-9973 4 Kleinheubacher Berichte 2005 2006 10.5194/ars-4-357-2006 http://www.adv-radio-sci.net/4/357/2006/ http://www.adv-radio-sci.net/4/357/2006/ars-4-357-2006.html http://www.adv-radio-sci.net/4/357/2006/ars-4-357-2006.pdf 357 360 2006-09-06 Investigation of RF transmission properties of human tissues D. Werber A. Schwentner E. M. Biebl biebl@tum.de Technische Universität München, Fachgebiet Höchstfrequenztechnik, Arcisstraße 21, 80333 München, Germany Technische Universität München, Lehrstuhl für Technische Elektrophysik, Germany RF transmission properties of human tissues were investigated in the frequency range from 50 MHz to 1 GHz. This work was motivated by the increasing interest in communication links between medically active implants and external interrogator units. We investigated theoretically and experimentally the transmission loss between an implant and an external interrogator unit. We assumed that due to the size of the implant a maximum area of only 1 cm² is available for the printed circuit antenna. The size of the external interrogator antenna is less restricted. The maximum depth of the implant beneath the surface of the body was assumed to be 10 cm. For the simulations we took the dielectric properties of skin, fat and muscle as published in the literature. For the measurements, an artificial muscle dielectric proposed in the literature was used consisting mainly of a mixture of water, sugar and salt. In simulation and measurements the reactive part of the impedance of the antennas was compensated numerically. In simulations and measurements we obtained a transmission loss between 30 dB around 100 MHz and 65 dB around 900 MHz. Gabriel,~C., Gabriel,~S.: Dielectric properties of biological tissues: I-III, Physics in Medicine and Biology, 41, 2231–22903, 1996. Hartsgrove,~G., Kraszewski,~A., and Surowiec,~A.: Simulated Biological Materials for Electromagnetic Radiation Absorption Studies, Bioelectromagnetics, 8, 29–36, 1987. Wolf,~B., Kraus,~M., and Sieben,~U.: Potential of microsensor-based feedback bioactuators for biophysical cancer treatment, Biosensors and Bioelectronics, 12, 301–309, 1997.