Reactive near-field region radiation of planar UWB antennas close to a dispersive tissue model

This paper focuses on the radiation properties of planar Ultra Wideband (UWB) antennas in the vicinity of a dispersive layered tissue model through the range of 0-30 mm above the body model surface. Radiation properties are investigated in terms of the realized maximum gain, total antenna efficiency and radiation patterns (the plots of realized gain) at different antenna-body distances. Two planar UWB antennas are simulated in free space in this study and at multiple distances to the tissue model. Results are analyzed and discussed based on the antenna theory. When the operation distance over the boundary of antenna's reactive field can be used, the performance close to free space can be achieved.