offers a complete procedure for the simulation and optimization of metamaterials with planar symmetry. The book begins with introduction of advanced modelling methods for the analysis of frequency selective surfaces with different types of substrates. The efficiency of the proposed techniques are studied and improved based on different ideas. Then, novel procedures for the optimization of such structures are investigated in order to select the most promising algorithms. These studies constitute the main concepts needed for the design of planar metamaterials. Subsequently, their application for realizing flat radar absorbers are focused. Structures are designed, fabricated and characterized which are capable of absorbing optimally the incident electromagnetic wave.