Scattering of lossy dielectric surfaces in full wave simulation of Maxwell's equations with dense grid and neighborhood impedance boundary conditions

We are proposing a new numerical method for solving the scattering problem for a 1D random rough surface with a high dielectric constant using Method of Moments (MoM). For sea water at L band, the dielectric constant can be as large as 75 + 61i which will require the usage of a dense grid. Traditional MoM solution on dense grid will end up with solving an impedance matrix equation with very large condition number which will lead to a slow convergence rate. The proposed Neighborhood Impedance Boundary Condition (NIBC) has taken advantage of the band nature of the impedance matrix and related the surface electric field and magnetic field within a pre-selected threshold. Simulation results show that NIBC is both accurate and fast compared to benchmark solution or Impedance Boundary Condition (IBC).