蜂窝夹芯结构作为天线罩最常用的透波材料,其电各向异性特征对电磁传输性能具有不可忽略的影响.本文基于各向异性蜂窝夹芯材料对电磁波水平极化和垂直极化分量的有效介电常数,建立了多层蜂窝夹芯材料的等效传输线网络传输方程,并给出了其传输系数的计算公式.该计算公式由于考虑了材料的三维各向异性特征,不仅理论上可以计算多层各向异性介质板对任意方向入射电磁波的传输系数,而且能够揭示出材料方向角对传输性能的影响规律.同时,通过传输线网络等效,其计算效率远高于有限元等方法.数值算例表明,本方法能够有效地揭示蜂窝夹芯材料的各向异性对其传输性能的影响,计算结果在入射角为0°—80°时与有限元法符合很好.
Honeycomb sandwiches are widely used as electromagnetic transparent materials for radomes. However, the electric anisotropy has a significant influence on the transmission performance. This work aims to investigate the electromagnetic transmission character- istics of the anisotropic sandwich panel. First, we deduce the effective permittivity of multilayered anisotropic sandwich material in the respect of the horizontal polarization and the perpendicular polarization components of the incident wave. Second, the transmission line network method related to the multilayered homogeneous medium is improved to simulate the electromagnetic transmission through honeycomb sandwiches and to calculate the transmission ratio. As the proposed method takes into account the three-dimensional anisotropy of each slab, it can simulate the transmission of plane wave with arbitrary incident direction in multilayered anisotropy sandwich panels, moreover, it can reveal the influence of material orientation on the transmission characteristics. Since the multilayer configuration is simulated by transmission line network, the proposed method is far more efficient than the finite element method. Numerical experiments indicate that the influence of the electric anisotropy on the transmission performance of honeycomb sandwich materials can be well revealed. In an incident angle range between 0 and 80 degrees, the simulation results fit well to the results obtained by the finite element method.