Edinburgh Napier University

  The standard finite-difference time-domain (FDTD) method requires extremely small time-step sizes when modelling electrically-small regions: the method can thus become impractical due to the unaffordable computation times required. Implementation of a quasistatic approximate version of FDTD can solve this problem. This approach is based on transferring the working frequency to a higher frequency, to reduce the number of time steps required. In order to prove the validity of the quasistatic approach, a three-dimensional FDTD program was used to directly model a single homogeneous or multilayered sphere inside a lossless or lossy problem space. By implementing the frequency scaling approach, the number of FDTD time steps can be reduced. The reflection on the interface layers inside the computational domain of FDTD is also reduced in lossless and lossy media.