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• A composite structured metamaterial absorber with good wave absorption performance was prepared to cover X-band and Ku-band perfectly at low thickness (2.2 mm). • Investigated the influence of different structural parameters and polarization angles on wave absorption and energy absorption. • The open-hole effect was discovered and proposed, and the study of the corresponding mechanism and influence law can provide technical and theoretical guidance for the design of metamaterial structures of other materials. • The bandwidth of the designed metamaterials is increased by 1.34 times compared with that of pure composite materials. • The combination of numerical simulations and experiments provides a good match between experiments and simulations. In this paper, propose the open-hole effect, which can improve the absorption effect of electromagnetic absorbers in the X- and Ku-band by regularly opening certain shaped through-holes in the dielectric material. Based on this effect, an ultra-wideband metamaterial absorber with a special open-hole structure is designed and successfully prepared by numerical simulation, and the effective wavelength bandwidth (absorption > 90 %) covers X- and Ku-band. By optimizing the dielectric material and structural parameters of the absorber, an ultra-broadband metamaterial absorber with a thickness of 2.2 mm, a maximum absorption rate of 99.35 % and an effective absorption bandwidth of 11.6 GHz was obtained. Simulations of TE and TM waves at different angles show that the absorber has excellent electromagnetic wave absorption at different angles of incidence (θ < 30°). [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]

• The composite film with two layers can correct the fluctuations in the initial stage of the force-sensitive curve and improve the stability of the force sensitivity at the initial stage. • The composite film has high force-sensitive properties in the compressive stress interval of 0–0.1 MPa, when the thickness of the film is 200–230 μm, the film has the highest sensitivity. • The force-sensitive film is the most stable and sensitive one among the current piezomagnetic force-sensitive films. Piezomagnetic sensor is a subject undergoing intense study. In this paper, a force-sensitive composite film with two layers was designed, and the force-sensitive properties of the film at σ ≤ 0.2 MPa was studied by inductance measurement. The composite film with a complex force-sensing mechanism can correct the fluctuations in the initial stage of the force-sensitive curve and improve the stability of the force sensitivity at the initial stage. Compared to the force-sensitive properties of Fe 78 Si 13 B 9 amorphous alloy film, the composite film's is significantly higher. When the thickness of the composite film is 180–250 μm, the film has high force-sensitive properties in the compressive stress interval of 0–0.1 MPa, the force-sensitive curve in the sensitive interval is linear approximation. When the thickness of the composite film is 200 μm and the test frequency f = 1 KHz, the sensitivity of the pressure sensor is as high as 0.27 μH/KPa in a wide pressure interval (0 ~ 0.06 MPa). When the thickness of the composite film is 230 μm and the test frequency is 1 KHz, the sensitivity of the pressure sensor is as high as 0.59 μH/KPa in a wide pressure interval (0 ~ 0.02 MPa). The force-sensitive film is the most stable and sensitive one among the current piezomagnetic force-sensitive films. In addition, it has broad application prospects. [ABSTRACT FROM AUTHOR]