Scattering Analysis of Large-Scale Coated Cavity Using the Complex Nonstandard FDTD Method With Surface Impedance Boundary Condition

Recently, we reported on the basic advantages of the complex-type surface impedance boundary condition (CSIBC), however, its validity has not been confirmed for practical problems. In this paper, we show the formulation of CSIBC, which includes corners, and the complex nonstandard finite-difference time-domain (CNS-FDTD) method with the CSIBC is applied to the scattering analysis of a large cavity coated with radar absorbing materials. As a result, it is shown that the CSIBC formulation is highly efficient at reducing the computer load. For our 3-D model, the CSIBC reduced the computer load to roughly 1/6⁴ that of the FDTD method.