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• New metamaterial design methods was proposed. • Great performance improvement in bandwidth compared with the initial material. • Lighter weight and more widely used. • Analysis of absorbing principle is comprehensive. The thickness and absorption width of electromagnetic wave-absorbing- materials remain a considerable challenge. This paper proposed a new design method for metamaterial absorbers. The absorber is composed of magnetic composites with a periodic structure. The effective absorption bandwidth (reflection loss <−10 dB) achieves 13.4 GHz, from 4.6 GHz to 18 GHz with 3.5 mm thickness (0.05 λ max ). There are two absorption peaks at 6.1 GHz and 10.8 GHz, the reflection loss reaches −20 dB and −15.6 dB, respectively. The loss mechanism is analyzed by analyzing the electric field distribution and surface current. Actual samples were prepared, their reflection losses were measured, and the test results verified the simulation results. [ABSTRACT FROM AUTHOR]

• The addition of magnetic materials broadens the effective absorption bandwidth. • Synergy between dielectric and magnetic losses strengthens microwave absorption. • The composite structure design improves the wave absorption performance. • 3 mm CSMMA has an effective absorption bandwidth of 11.53 GHz. The requirements for electromagnetic wave absorbing materials are increasing as modern technology advances. However, traditional absorbing materials have limitations due to their thickness and incompatibility with high and low frequencies, and metamaterial absorbers have limitations due to their narrow effective absorption bandwidth. This paper overcomes these problems and designs and prepares a broadband, thin and light metamaterial absorber. The effective absorption bandwidth of the composite structure metamaterial absorber (CSMMA) with a thickness d 1 of 3 mm reaches 11.55 GHz with the addition of FeSiBPCuY 5 p/paraffin magnetic composite into the metamaterial absorber and the optimization of the structural parameters. The composite structure design greatly improves the absorption performance of the metamaterial absorber. The advantages of the tunable frequency absorption characteristics of the metamaterial absorber and the high-frequency broadband absorption performance of the magnetic wave absorbing materials are fully exploited in the design of the absorber. Which is of great significance for the development of broadband and thin-absorbing materials. This absorber can be adapted to meet the needs of practical applications by adjusting its structural design, expanding its range of applications and having a substantial influence on the use of wave absorbing materials. [ABSTRACT FROM AUTHOR]

Firstly, the spherical Fe50Ni50 powders, particle size about 100 nm, were prepared by liquid phase reduction method, and then were mixed with butyl rubber (IIR) dispersed in liquid. Fe50Ni50 powders/IIR nanocomposite films, powder mass fraction was 65 wt%, were harvested through being mixed and milled lastly. The force sensitive properties of the films were studied under the condition of that the loading/unloading speed of the stress was 0.10 mm/min controlled by the LYYL-500N high-grade microcomputer controlling compression-testing machine, and the test frequency of impedance (Z) was 1 kHz tested with the TH2816B LCR digital electric bridge. Results show that Fe50Ni50 powders can be dispersed uniformly as nanometer scale in this nanocomposite by liquid phase mixing method. And the Fe50Ni50 powders/IIR nanocomposite film, thickness 185 μm, has excellent force–sensitive properties when the stress is between 0.20Mpa and 0.90Mpa. The impedance ∼ stress curve appears approximately linear decline, and stress sensitivity |k| value is stable in 40–60, stability S value is about 1∼ 2 kΩ, and the film enters into a steadily sensitive stage responding to stress. [ABSTRACT FROM AUTHOR]

In recent years, the development of lightweight broadband absorbers has always been pursued by researchers. In this paper, a low-frequency, broadband and lightweight absorber is designed and prepared by combining the metamaterial structure with the magnetic composite material. First of all, the quality of the absorber was low, which was 40% lower than that of traditional absorber composite materials. Secondly, the absorber had excellent absorbing effect, and its absorbing bandwidth (bandwidth with reflectivity less than −10 dB) reached 6.72 GHz, and its RL min (minimum reflection loss) value had dropped to − 23.94 dB. Finally, the absorber also had obvious effects at low frequencies, the absorber's RL min value reached − 10.10 dB at 7.36GH. Simultaneously, the experimental results also verify the above results very well. Therefore, this kind of absorber gives full play to the advantages of magnetic composite material and metamaterial structure. This design concept provides a new development path for the design of absorber materials, and will also play a huge role in promoting the application of absorbing materials in military and civilian fields, such as the research and development of a new generation of stealth fighters. [ABSTRACT FROM AUTHOR]

To meet the current requirements for absorbing materials with broadband, lower thickness, and lower density, the FeNi@C@Fe 3 O 4 magnetic powders with a density of 1.75 g/cm3 are constructed by the hydrothermal method and the liquid phase reduction method. The powders have good matching performance with air impedance in the band of 0.3 GHz ~ 18 GHz, and can consider both dielectric loss and magnetic loss-absorbing mechanisms. The loss tangent, tgδ, of the powders is 0.4–0.5. The powder coat is designed by using the interference absorption mechanism. When the thickness of the coat is 1.8 mm, the absorption peak of the coat is about − 30 dB. The coat has a maximum of effective absorption band for 12.2 GHz ~ 17.3 GHz, and the effective absorption bandwidth is 5.1 GHz. When the glass fiber/epoxy resin composite material of thickness 0.5 mm is coated on the FCFp coat of thickness 1.7 mm, the effective absorption band is further widened to 11.9 GHz ~ 17.6 GHz, and the effective absorption bandwidth reaches 5.7 GHz. The FeNi@C@Fe 3 O 4 powders have the characteristics of dielectric and magnetic loss-absorbing materials, and have the remarkable advantages of the wider effective absorption bandwidth and the lower density, which is a kind of high-efficiency absorbing material with outstanding comprehensive absorption performance. [Display omitted] [ABSTRACT FROM AUTHOR]