Optimization of Frequency Selective Surfaces

Frequency selective surfaces are important in many electromagnetic applications since they transmit electromagnetic energy for some frequencies and reflect for others. There is a variety of tools available for the design of the interior structure of frequency selective surfaces. Here, we propose to use gradient-based optimization techniques in combination with a time-domain hybrid Finite Element Method (FEM) and Finite-Difference Time-Domain (FDTD) scheme for the design of frequency selective surfaces. The sensitivity of the goal function is computed cheaply from the solution of an adjoint field problem, which yields the steepest descent direction with respect to all design parameters