Frequency-selective coatings based on EBG structure combining carbon nanotubes with polymeric or ceramic substrate

We present electromagnetic bandgap (EBG) multilayer films or slabs acting as frequency-selective coatings able to absorb or reflect microwave signals in specified frequency bands. The basic structure exhibits high absorption index over a broad spectrum of frequencies, from 8 to 70 GHz. It is composed of thin conductive layers based on polymer and carbon nanotubes (CNT) that are stacked in gradient of conductivity. Changing physical properties of dielectric spacers between the conductive layers allows creating narrow high-absorption bands at defined frequencies (even lower frequency). This multilayer approach offers a smart and versatile solution for tuning the selectivity of EBG performances.