涂料型微波吸收材料计算机辅助设计

涂料型微波吸收材料计算机辅助设计可以计算各种材料(不同的ε′、ε″、μ′和μ″)在不同的涂层厚度和工作频率下的微波吸收性能。如果定义能允许的最大反射系数为反射系数阈值,则可设计出某一频率范围内或某一中心频率附近反射系数小于该阈值的最大工作宽带以及与之相应的材料参数,如果已知工作带宽,则可设计出在此带宽内最小的反射系数阈值和相应的材料参数。例如,在涂层厚度d≤2mm,μ′≤2,μ″≤2,ε′任意可变,ε″≤0.5ε′的条件下、可设计出:在7—13GHz范围内,反射系数小于-20 db的最大工作带宽是4.1GHz;中心频率为10GHz,反射系数小于-20 db的最大带宽为3.3GHz;在8—10 GHz工作带宽内,最小反射系数阈值为-22db。通过辅助设计还可以了解涂层厚度和材料参数变化时,材料参数随频率变化时,以及斜入射时对微波吸收材料性能的影响。

THE COMPUTER-AIDED DESIGN OF COATING FOR MICROWAVE ABSORPTION

The computer-aided design of coating for microwave absorption is discussed in this paper. For given complex permitivity and permeability, it is easy to calculate the microwave absorbing performance of materials coated onto perfect conductors. We are able to obtain the maximum bandwidth and find corresponding material parameters under specific frequency region or near the center frequency, for which the reflection coefficient is less than critical value specified in advance. It is also easy to get the the minimum critical value of reflection coefficient and corresponding material parameters for specific frequency band. For example, when coating thickness is less than or equal to 2mm and the parameters are within certain range, we are able to get a bandwidth as large as 4.1GHz for frequencies ranging from 7 to 13GHz or a bandwidth as large as 3.3GHz for center frequency at 10GHz if the critical value of reflection coefficient is equal to -20db, and the critical value of reflection coefficient as little as -22db if the frequency ranges from 8 to 10GHz. It is possible in the computer-aided design to understand the influence of coating thickness, material parameters and incident angle on the frequency dependance of reflection coefficient