Design of Multi-Layer Planar Wave Absorber Using Time Domain and Adjoint Sensitivity Analysis

In this paper, the adjoint sensitivity analysis with an iterative first-order gradient descent optimization technique is proposed in conjunction with the finite-difference time-domain (FDTD) method to design a broadband multi-layer planar electromagnetic wave absorber made of the expanded polystyrene mixed with graphite powder. The result obtained from the proposed design method is compared with the point frequency matching method. Smaller thicknesses and lower carbon content of a multi-layer planar absorber are obtained which can reduce the absorber weight.