Electromagnetic Characterization of Composite Materials and Microwave Absorbing Modeling

This book chapter is based on the experimental activities conducted mainly at Sapienza University of Rome: Astronautic, Electric and Energetic Engineering Department in collaboration with University of Maryland, Institute for Research in Electronics and Applied Physics (IREAP). A branch of scientific research about composite materials is focused on electromagnetic characterization and subsequent application of electric conductive polymers. The use of such structures is relevant in aerospace/aeronautics, for electromagnetic (EM) protection from natural phenomena (lightning), and intentional interference with radar absorbing materials (RAM), in nuclear physics for shields adopted in particle accelerators, and for nuclear EM pulses (NEMP) protection, in electromagnetic compatibility (EMC) for equipment-level shielding, high-intensity radiated fields (HIRF) protection, anechoic chambers (for the realizations of wedges and pyramidal arrays), and human exposure mitigation. In this chapter, composite reinforced by carbon nanostructured materials are considered, mainly because of their interesting electromagnetic characteristics, such as high electrical conductivity and excellent microwave absorption. Composite materials as well their absorption capability are analyzed and numerical design of wide frequency band microwave absorbing structures is presented and discussed in details. It is crucial to highlight the need of interdisciplinary research fields to go through nanomaterials: besides nanotechnology, also electromagnetic wave propagation theory, composite materials manufacturing techniques, evolutionary computation algorithms, and use those to design the “quasi perfect absorber” are strongly required. In particular, we propose an inhomogeneous multilayer absorber made of micrometric graphite (at different wt%), and nanometric carbon particles (SWCNTs, MWCNTs, CNFs, at different wt%). At the end, an improvement of the traditional absorbers has been achieved upon optimization through an in-house winning particle optimization (WPO) algorithm, this last appositely conceived for absorbers optimization. Main goal of the presented work is to optimize the absorbers