Abstarct: Among the absorbent materials of electromagnetic waves, ferrite materials due to their properties such as losses, high chemical stability and corrosion resistance can be a good option for use in radar covers. Furthermore, using radar absorbent coatings and installing them on the body of the vessels we can attenuate and absorbed a wide range of radar waves, this cause hiding the target from the radar. Nano materials due to unique electrical and mechanical properties are a good option for absorbing electromagnetic waves. Nano-baxsed composite materials can be made lightweight, inexpensive and easy. by using nanoparticles iron, nickel and cobalt in the manufacture of ferrite nano composites with designing a pattern for reducing radar cross-section, it is significantly capable of reducing the radar cross-section in the frequency range of radar waves. These materials like a millimeter cover are lined on the body of the vessels and it can hide them from enemy radars. In this thesis new method for reducing materials radar cross-section RCS in a wide frequency range using synthetic magnetic conductor surfaces is presented AMC. This thesis shows that the use of magnetic substrates can increase the bandwidth performance of AMC structures. The main idea of this RCS structure over a wide frequency range in this thesis baxsed on the use of two AMC structures with different dimensions that work in two different frequency bands. But the dimensions and operating frequencies of these two AMC structures are adjusted to remain within a wide frequency range of the reflective phase difference of the two structures near 180 degrees and thus neutralize each other's reflection and RCS structure decreases. The simulation result shows that this method can reduce the RCS by up to 20 dB for a mextal structure in a bandwidth of about 50%.