UWB power propagation for bio-medical implanted devices

This work presents a study of ultra wideband (UWB) technology to compute the energy transmission level as an electromagnetic impulse traveling from the transmitter antenna into the human body, and reaching the receiver antenna. The consideration is based on two center frequencies at 3.5 GHz which occupies 1 GHz bandwidth and at 6.1 GHz occupying 6 GHz bandwidth. A small discone antenna with gain of 1.8 dBi is employed as the transmitter antenna and a designed implantable patch antenna with gain of 4 dBi is also used as the receiver antenna. The distance between two antennas is 23.6 mm and the tissue attenuation has been considered for two layers including skin and fat with thickness of 2 mm and 9.6 mm respectively. The computation is accomplished for one way-link UWB communication system with respect to FCC regulation, UWB antenna characteristic and Biological tissue model focusing on attenuation affects. The attenuation is based on the response of the transmitted incident power to reflection, absorption and thickness of the human tissue including frequency-dependent parameters such as permittivity and conductivity. Computer simulation results demonstrate the power comparison for two center frequencies in terms of bandwidth and attenuation. Since the lower band of UWB is suitable for radiation into the human body due to the greater penetration of signals, the results indicate that despite the increasing frequency from 3.5 GHz to 6.1 GHz, there is only minor power variations at the receiver.