UWB On-Body Radio Channel Modelling Using Ray Theory and Sub-band FDTD   Method
  This paper presents the ultra-wideband (UWB) on-body radio channel modelling using a sub-band Finite-Difference Time-Domain (FDTD) method and a model combining the uniform geometrical theory of diffraction (UTD) and ray tracing (RT). In the sub-band FDTD model, the frequency band (3 - 9 GHz) is uniformly divided into 12 sub-bands in order to take into account the material frequency dispersion. Each sub-band is simulated separately and then a combination technique is used to recover all simulations at the receiver. In the UTD/RT model, the RT technique is used to find the surface diffracted ray path while the UTD is applied for calculating the received signal. Respective modelling results from two-dimensional (2-D) and three-dimensional (3-D) sub-band FDTD and UTD/RT models indicate that antenna patterns have significant impacts on the on-body radio channel. The effect of different antenna types on on-body radio channels is also investigated through the UTD/RT approach. 
Yan Zhao, Akram Alomainy, Yang Hao, Clive Parini