The Study Of Quasi Three-Dimensional Metamaterial In Electromagnetic Control

With the development of modern communication technology,natural materials cannot meet the diverse needs in electromagnetic control.Therefore,the study of artificial electromagnetic materials(metamaterials)has gradually become one of the research focuses.As a new type of material,metamaterials can not only control the permittivity and permeability of materials,and design specific materials on demands,but also realize various electromagnetic phenomenon through kaleidoscopic microstructures.And it provides a convenient method for the design of many electromagnetic equipment.Compared with ordinary natural materials,metamaterials' properties can be adjusted manually and for this reason they show significant advantages.According to dimension,metamaterials can be classified into metasurfaces,three-dimensional metamaterials,and quasi-three-dimensional materials with a certain thickness.Quasi-three-dimensional metamaterials can break through the limit of twodimensional metamaterials due to its advantages in dimension and structure,and broaden the scope of application.Moreover,the quasi three-dimensional metamaterials overcome the shortcomings of the three-dimensional metamaterials,such as bulkiness,excessive volume,and complicated structure,and have better application prospects.3D printing is a low-cost and high-efficiency method for achieving quasi-threedimensional metamaterials.Fused deposition modelling(FDM)is the most representative method among many 3D printing technologies.It has a simple process,a wide variety of consumables,and is low cost.Therefore,it is the most widely used 3D printing technology.Using FDM technology,researchers can more easily explore and manufacture quasi-three-dimensional metamaterials,shorten the research cycle,and it can also be applied to small-scale batch production.Chiral metamaterials have received great attention in control of electromagnetic wave transmission,and can be used to achieve bizarre optical properties such as optical activity,circular dichroism,and asymmetric transmission.However,it often has a complex three-dimensional chiral structure,which is difficult to make with traditional processes.Therefore,the application of 3D printing in chiral metamaterials is of great significance to the study of electromagnetic control.In this article,we design several chiral quasi three-dimensional metamaterials to achieve optical properties based on 3D printing technology,such as circular dichroism and asymmetric transmission.The main work is as follows:1.Two complementary double-layer ellipse / elliptical slot structures are designed in this paper.The structures adopt the stacking method to introduce chirality.Through numerical simulation,it is confirmed that the circular dichroism of the elliptical slot structure is superior to the double-layer elliptical structure.A 7 × 7 sample with a double-layer elliptical slot structure was fabricated by 3D printing and its transmission and CD parameter was calculated through experiments.The results were basically consistent with the simulation.2.In this paper,we design and compare the asymmetric transmission characteristics of the all-dielectric and metal double-L structure.The metal structure has a better effect and the peak value of the asymmetric transmission coefficient can reach 0.76.3.Two quasi-three-dimensional metamaterials with three-dimensional unit structure are designed.The first structure is composed of twisted split ring,which can achieve an asymmetric transmission parameter close to 1.Its working band can be broadened by adding another rotating slit.and realize broadband asymmetric transmission from 9.8GHz to 14 GHz.The second structure has dual-band asymmetric transmission characteristics,and the peak value of the asymmetric transmission coefficient can reach 0.96 at 10.8GHz.The 3D printing technology and chemical plating were used to fabricate samples and verify the property of these two metamaterials.Experimental results and simulation results have similarity,but there is difference due the technological problems in fabrication.