Study On The Absorbing Properties Of Carbon-based Absorbing Materials And Metamaterials Composite Structues

With the progress of science and technology and the expansion of the field of absorbing wave,people's demand for the performance of absorbing wave materials is gradually developing towards the direction of "lighter,thinner,wider,lower and stronger".Because of the problems of high density and narrow broadband,the traditional absorbing materials have been greatly restricted in the application field.In recent decades,carbon-based absorbing materials and metamaterials have become the focus of attention.Carbon-based absorbing materials have low density and excellent absorbing performance in the high frequency range,but the absorbing frequency range is difficult to be extended to the low frequency.As a kind of adjustable artificial electromagnetic material,metamaterials can perfectly absorb the microwave in specific frequency band,but it is also difficult to expand the bandwidth under the premise of keeping thin and light enough.The combination of carbon-based absorbing materials based on different absorbing mechanisms with metamaterials provides a new possibility for improving the absorbing properties of materials.At present,many researches have been made on the composite structure of metamaterials and other absorbing materials,but the coupling mechanism between the materials is still unclear.Therefore,with the use of HFSS,this article studied the absorbing properties of multi-walled carbon nanotubes/graphene absorbing sponge as a typical representative of carbon absorbing materials.Then,combing the carbon absorbing material with metal and all-dielectric metamaterials of two different type respectively,the absorbing properties of composite structure with the material parameter change of carbon absorbing material and metamaterials and the way of combination and mutual action between these two kinds of materials are discussed.The results show that the reflection loss curve of carbon-based absorbing material plates moves towards low frequency as the real part of relative dielectric constant increases.The increase of the tangential value of the loss angle will make the absorption intensity of the carbon-based absorbing material plate increase first and then decrease,and the increase of the thickness of the plate will make the absorption peak of the carbon based absorbing material plate move to the low frequency and increase the bandwidth.In the study of the composite structures of carbon-based absorbing materials and two metal-based metamaterials,it is found that the resonance of carbon-based absorbing materials is affected by the high real part of the relative dielectric constant or the tangent of the loss angle.The "electric field thickness" of metamaterials exists in the process of resonance.In the composite design of metamaterials and other materials,not only the superposition of physical size,but also the superposition of materials in the electric field should be considered.For metal-based metamaterials loaded with lumped elements,adjusting the lumped value of metamaterials can effectively adjust the absorbing performance of composite structures.The results show that the increase of the real part of the dielectric constant has little effect on the magnetic resonance peak and the higher resonance peak of the composite structure,but the electric resonance peak will shift to the left.The tangent of the loss angle is the main reason for the overall increase of the absorption strength of the composite structure.The resonant peak of the composite structure is affected by the loss of the electric field.The increase of the relative permittivity and radius of the dielectric sphere has a similar effect on the performance of the composite structure.The position and strength of the resonant peak of the composite structure can be flexibly adjusted by changing the material parameters of the carbon-based absorbing material and the dielectric ball.