Time domain modelling. Integral equations, finite differences and experimental results

We have described the fundamental assumptions present in two numerical time domain methods based on the Electric (or Magnetic) Field Integral Equations and Maxwell's equations. The cause of late time instabilities in the former was analysed, and a practical and effective method of eliminating them was presented. Numerical results of the methods for some idealised problems were presented. Discrepancies in the decay envelope of the backscattered pulses were attributed primarily to the finite thickness of the FDTD plates, as opposed to the infinitely thin structures used in the integral equation representation. Upon modifying the conductivity in the FDTD plate model to make the plate thin, in the sense that its thickness is comparable to its skin depth, we find significantly improved agreement.