Radar-absorbent material (RAM), often as paints, are used especially on the edges of metal surfaces. While the material and thickness of RAM coatings can vary, the way they work is the same: absorb radiated energy from a ground or air based radar station into the coating and convert it to heat rather than reflect it back.
Current technologies include dielectric composites and metal fibers containing ferrite isotopes. Paint comprises depositing pyramid like colonies on the reflecting superficies with the gaps filled with ferrite-based RAM. The pyramidal structure deflects the incident radar energy in the maze of RAM. A commonly used material is known as "Iron Ball Paint‟.
Iron ball paint contains microscopic iron spheres that resonate in tune with incoming radio waves and dissipate the majority of their energy as heat, leaving little to bounce back to detectors. FSS are planar periodic structures that behave like filters to electromagnetic energy. The considered frequency selective surfaces are composed of conducting patch elements pasted on the ferrite layer. FSS are used for filtration and microwave absorption.