Design And Electromagnetic Properties Of Textile-based Metamaterials

With the development of radar technology,people's requirements for stealth technology are getting higher and higher.Since the advent of ferromagnetic microwires,their permittivity and permeability are complex,which makes them absorb electromagnetic waves.The excellent electromagnetic properties have been studied by many scholars.On the basis of the textile structure,the ferromagnetic microwires are woven into the fabric in a manner of weft lining.The period length of the ferromagnetic microwires in the fabric is adjusted by changing the length of the weft yarn length line,and the spacing between the ferromagnetic microwires is adjusted by changing the thickness of the weft yarn.The results show that in the two-dimensional textile structure,the Co_67.05Fe_3.85Si_14.17B_11.53Ni_1.44Mo_1.66 microwire is woven into the quartz fiber fabric as a preform to prepare the metacomposites.In the X-band(8.2 to 12.4 GHz),the metacomposites containing ferromagnetic microwires has a negative permittivity in the vertically arranged sample,and the dielectric response mode follows the Lorentz oscillator mode.The metacomposites with a periodic cycle length of 2.5mm achieved a microwave absorption level of up to 34%.The metacomposites with a periodic cycle length of 7.5mm has less interlacing points and the longest surface float length,so it has a tensile strength of 458MPa.The electromagnetic wave propagation of the composite prepared by the Co₆₈Fe₄Si₁₁B₁₃Ni₁Mo_2.3 microwire in the X and Ku-band(12.4?18GHz)was evaluated and studied by experiments and simulations.For composites composed of vertically aligned ferromagnetic microwires,the permittivity becomes negative in certain frequency bands for 1mm and 0.5mm pitch.The simultaneous presence of short period bending lengths and spacing facilitates the expansion of the frequency band in which the composite exhibits a single negative metacomposites behavior.Due to the domain structure rearrangement of ferromagnetic microwires,the characteristic peaks of permeability are highly dependent on the periodic bending length and spacing.Similarly,the dynamic response to electromagnetic waves is enhanced when the periodic bending length and spacing are shortened.A significant transmission window was observed due to the negative permittivity occurring at the plasma frequency.The increase in the periodic bending length affects the width of the transmission window,and as the spacing decreases,both reflection and transmission decrease,resulting in an increase in absorption of 36%.According to the simulation results,the main loss of the composite of the fabric structure in the X and Ku bands comes from the electrical loss,and the small periodic bending length tends to form a uniform power loss distribution.The reduction in the spacing of ferromagnetic microwires results in strong long-range dipole resonance and magnetic domain wall motion,thereby improving microwave absorption.In the three-dimensional textile structure,the Co_67.05Fe_3.85Si_14.17B_11.53Ni_1.44Mo_1.66 microwire was woven into the quartz fiber fabric as a preform to prepare the metacomposites by the weft yarn lining.Compared with the two-dimensional 34%microwave absorption performance,the structure exhibits a good microwave absorption level of 67%in the Ku band due to good impedance matching at a ferromagnetic microwires pitch of 2mm.In addition,the mechanical impact has little effect on the electromagnetic properties of the composite.Therefore,the use of textile structural metacomposites containing ferromagnetic microwires in stealth materials seems to have great potential.