This paper describes the relationships between the surface wave attenuation properties and the electromagnetic parameters of radar absorbing materials (RAMs). In order to conveniently obtain the attenuation constant of TM surface waves over a wide frequency range, the simplified dispersion equations in thin absorbing materials were firstly deduced. The validity of the proposed method was proved by comparing with the classical dispersion equations. Subsequently, the attenuation constants were calculated separately for the absorbing layers with hypothetical relative permittivity and permeability. It is found that the surface wave attenuation properties can be strongly tuned by the permeability of RAM. Meanwhile, the permittivity should be appropriate so as to maintain high cutoff frequency. The present work provides specific methods and designs to improve the attenuation performances of radar absorbing materials.

Aimed at broadband microwave absorption, we present the linear polarization conversion metasurface (MS) by a novel design of a two-bit matrix-type coding method. The coding patterns are applied to a dielectric substrate and a magnetic substrate. The radar cross section (RCS) reduction curves of different matrices can fully verify the independence and correctness of the matrix-type coding method. As shown in simulation, the RCS reduction of 8 dB by a metal pattern with a dielectric layer has been achieved in the frequency range of 6–15 GHz. When the matrix-type coding pattern is placed in the middle of double-layered magnetic absorbing materials (MMs), a 10 dB RCS reduction can be achieved in the range of 8–16 GHz. Besides, the metal patterns can improve the high frequency reflection loss performance and broaden the absorption bandwidth of MMs almost without changing the thickness. The experimental results can nicely reproduce the simulated results. The correlative RCS reduction mechanism is further explored. This model provides a new idea in the design of coding MS, which implicates a potential application in stealth technology.

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Co0.5Ni0.5Fe2O4 fibers with a diameter of about 270 nm and a length of about 10 μm were synthesized by a microemulsion-mediated solvothermal method with subsequent heat treatment. The Co0.5Ni0.5Fe2O4 fibers/reduced graphene oxide (RGO) composite was prepared by a facile in-situ chemical reduction method. The crystalline structures and morphologies were investigated based on X-ray diffraction patterns and scanning electron microscopy. Magnetization measurements were carried out using a vibrating sample magnetometer at room temperature. Co0.5Ni0.5Fe2O4 fibers/RGO composites achieve both a wider and stronger absorption and an adjustable surface wave attenuation compared with Co0.5Ni0.5Fe2O4 fibers, indicating the potential for application as advanced microwave absorbers.