▎ 摘　　要

With the rapid development of electronic technology and military techniques, electromagnetic protection materials are becoming more and more significant to people. Harmful electromagnetic radiation not only affects the normal operation of electronic equipments and military security, but also has a serious impact on human health. At present, using absorbing and shielding materials are effective means to reduce the harm of electromagnetic waves. In this project, graphite, graphene and silver-coated copper powder coated composites were prepared using PU-2540 polyurethane and adopting a coating process for the substrate on plain polyester/cotton fabric. The controlled variable method was used to prepare and study the electromagnetic properties of single-layer coating composites with different functional particle contents. The result showed that within the frequency range of 0.01GHz similar to 1.0GHz, when the total mass of functional particles was 48% relative to that of the polyurethane, the value of the real part of the dielectric constant of the sample remained the largest and its polarization ability was the strongest. Within the frequency range of 0.08GHz similar to 1.0GHz, when the content of functional particles was 24% relative to that of the polyurethane, the value of the imaginary part of the dielectric constant and the loss of the tangent value of the sample kept the maximum, and the loss and attenuation ability with respect to electromagnetic waves were both the strongest. Within the frequency range of 1.3GHz similar to 2.0GHz, when the content of functional particles was 36% relative to that of the polyurethane, the value of the reflection loss of the sample was -26.93dB, and the minimum value of the reflection loss was obtained at a frequency of 1.6GHz, at the moment of which, the absorbing property of the sample was the best.