电磁窗桁架阻挡比对天线口径场影响分析

Influence of MSF radome blocking rate on antenna aperture

基于感应电流率理论,提出了将阻挡面积与口径场分布相结合的阻挡比计算方法,修正了传统算法存在的入射场分布不均匀问题,分析了金属桁架电磁窗中金属桁杆的散射效应,研究了桁架阻挡比在特定天线口径场分布下对天线传输特性的影响,以卡塞格伦天线为例计算了平行极化波入射桁杆阵列时的插入损耗,并将计算结果与FEKO软件中矩量法仿真结果进行了对比验证.结果表明:考虑天线口径场的阻挡比算法相比传统算法在计算精度上有了较大提高,最大误差不超过0.1dB;金属桁架电磁窗的插入损耗不仅受阻挡面积与感应电流率的影响,还与天线口径场能流密度分布有关;减小阻挡比,是设计低损耗电磁窗的有效途径.

Based on the theory of induced current rate,a method of calculating the relative shading rate combined the shielding area with the aperture field distribution is proposed.The problem of the inhomogeneity of the incident field in the traditional algorithm is modified.And the scattering of the metal bar in the electromagnetic window is analyzed.The effect of the grid shading rate on the antenna transmission characteristics under the aperture distribution of a specific antenna is discussed.The insertion loss of the planar array is calculated.The results are compared with the method of moments（MOM）simulation results using the FEKO software.The results show that the relative blocking algorithm improves the accuracy greatly with the maximum error less than 0.1 dB compared with the traditional algorithm.The insertion loss of the electromagnetic window is not only affected by the shielding area and the induced current rate,but also by the aperture field energy flow density distribution.Reducing the relative blocking rate is an effective way to design the low-loss radome.