Simulation And Simulation Of Broadband Microwave Absorption Of Flexible Composite Materials In The Microwave Section

With the rapid development of electronic technology,electromagnetic radiation is increasing.The deteriorated electromagnetic environment will not only interfere with the normal work of electronic instruments and equipment,but also affect human health.In military field,the international competition of weapons and equipment is becoming increasingly fierce.Due to the rapid development of modern detection technology and precision-guided weapons,which poses a great threat to the survival of weapons,it is imperative to study the stealth of weapons.The flexible absorbing material is one of the materials that cannot be ignored in the fields of military defense and civilian technology,such as military stealth,microwave anechoic chamber,microwave communication,electromagnetic information leakage protection,electromagnetic interference protection,and electromagnetic radiation protection.With the rapid development of electromagnetic shielding,stealth technology,and computational electromagnetics in recent years,the design and development of flexible absorbing materials have been focused.The ideal flexible absorbing material should have following characteristics,absorption frequency bandwidth,light weight,thin thickness,well physical and mechanical properties,and wide application range.In this paper a three-dimensional model of a double-layer coating fabric based on traditional coating processes and basic characteristics of textiles was built.Through simulation calculations,the absorbing performance of graphite / silicon carbide double-layer coating fabrics in the frequency range of 1GHz-20 GHz is predicted.And the real object is processed.The closed-field test method is used to test its actual absorption rate in the frequency range of 5.85GHz-8.2GHz.The relative error is8.72%,which can be in good agreement.The credibility of the prediction results and the internal simulation calculation model was verified.Then,based on the propagation mechanism of electromagnetic waves in the medium and the design theory of electromagnetic metamaterials(electromagnetic metamaterials),three flexible ultrathin wideband microwave absorbing materials in the microwave band were designed,which are rectangular surface flexible broadband absorbing materials and triangular surface flexible.Broadband absorbing material and hexagonal surface layer flexible wideband absorbing material.Using the analysis methods of equivalent impedance calculation,surface current distribution,energy loss,equivalent circuit,etc.,the absorption principle of three electromagnetic ultra-medium flexible ultra-thin wide-band absorbing materials in the microwave band is explained in detail,and their advantages and disadvantages are analyzed through comparison.The result indicates:When transverse radio waves or transverse magnetic waves is incident perpendicularly,the operating frequency of the rectangular wide-band flexible broadband absorbing material is 8GHz,and the absorptivity in the frequency range of4.08GHz-11.28 GHz is greater than 90%,and the relative bandwidth is 93.75%.The overall thickness is approximately 1.7mm,it is an ultra-thin,wave-absorbing flexible composite material that is not affected by the direction of incidence,suitable for c-band and x-band;the working frequency of the flexible surface wide-wave absorbing material with a triangular surface layer is 15 GHz,and the absorptivity in the frequency range of 11.3GHz-18.9GHZ is greater than 90%,and the relative bandwidth is 50.33%.The overall thickness is only 1.3mm.It is an extremely thin,absorbing flexible composite material that is basically unaffected by the direction of incidence and suitable for the Ku-band;The working frequency of the hexagonal surface flexible broadband absorbing material is 14.5GHZ,and the absorption rate is greater than 90% in the frequency range of 9.6GHz-17.84 GHz,the relative bandwidth is 60.06%,and the overall thickness is only 1.3mm.A extremely thin,absorbing flexible composite material that can be incident at a large angle in a fixed incidence direction,suitable for x-band and Ku-band.