Efficient implementation of the time domain surface impedance boundary conditions for the boundary element method

Efficient implementation of the time domain surface impedance boundary conditions on the surface of homogeneous lossy dielectric body for the space-time domain surface integral equations for the electric and magnetic fields is proposed. The governing equations are transformed by using the perturbation techniques in small parameters, equal to the ratio of the penetration depth and body´s characteristic dimension. As a result, the terms, containing time-convolution integrals, are moved from the left-hand side to the right-hand side of the integral equations, so that the computer resources required for numerical realisation of the formulations are greatly reduced. A numerical example is included to illustrate the theory