The Tx/Rx common aperture system not only needs to suppress out-of-field stray light, but also needs to suppress the influence of optical surface backscatter on detectivity. Backscatter generated by optical surfaces is often the dominant source of stray radiation that causes T/R isolation problems, and the black surfaces chosen for baffles also play a significant role in stray light suppression. Four commonly used optomechanical structure surfaces scattering BRDF data are measured, emulated and used. CFRP is selected as the baffle material, for the processing performance, cost performance and thermal control difficulty. A comparison is made between theoretical and experimental results for clean and particle contaminated ultra-smooth optical surface (CL= 800) scattering BRDF data. With the help of Mie theory and measured BRDF, the study improved the fitting accuracy of the Harvey-Shack model for the contaminated micro roughness surface. The Harvey-Shack model modeling coefficients of the particle contaminated micro-roughness surface are = 0.12, = 0.08, and =-2.2. The scattering radiation introduced by particulates reduces the T/R isolation of the space-agile Tx/Rx common aperture system by 3.74 dB. Measurement results of particulates reducing the T/R isolation by 4.05 dB, verified the accuracy of particle contaminated surface BRDF modeling.

中文翻译：

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空间灵活的 Tx/Rx 共孔径系统中的双向反射分布函数 (BRDF) 测量、建模和应用


Tx/Rx共孔径系统不仅需要抑制场外杂散光，还需要抑制光学表面后向散射对探测率的影响。光学表面产生的反向散射通常是导致 T/R 隔离问题的杂散辐射的主要来源，并且为挡板选择的黑色表面在杂散光抑制方面也发挥着重要作用。对四种常用光机械结构表面散射 BRDF 数据进行了测量、仿真和使用。考虑到加工性能、性价比和热控制难度，选择CFRP作为挡板材料。对清洁和颗粒污染的超光滑光学表面（CL= 800）散射 BRDF 数据的理论和实验结果进行了比较。研究借助Mie理论和实测BRDF，提高了Harvey-Shack模型对污染微粗糙表面的拟合精度。颗粒污染微粗糙表面的 Harvey-Shack 模型建模系数为 = 0.12、 = 0.08 和 = -2.2。颗粒物引入的散射辐射使空间灵活的 Tx/Rx 共孔径系统的 T/R 隔离度降低了 3.74 dB。颗粒物的测量结果使T/R隔离度降低了4.05 dB，验证了颗粒污染表面BRDF建模的准确性。