红外低发射率隐身涂层对太赫兹波的反射光谱研究

为研究红外低发射率隐身涂层对太赫兹波的反射特性，制备了红外低发射率隐身涂料，测试了其可见光效果、红外热像图及红外发射率等特性参数。以土黄色红外低发射率涂料为测试样品，利用透射式太赫兹时域光谱系统获得了样品在太赫兹波段的复折射率。分析了特征矩阵理论，并利用特征矩阵理论计算了涂层厚度(0.3~0.5 mm）与入射角度(0°~60°)的变化对入射太赫兹波反射特性的影响。结果表明，在相应厚度及入射角度范围内，太赫兹波在0.8 THz频率下具有多个反射峰值，最高值可达90%以上，有利于实现太赫兹波对红外低发射率隐身涂层下金属目标的探测。此外，涂层厚度变化对入射太赫兹波反射率具有较大影响，涂层越厚，太赫兹波的反射振荡越多，反射峰值越大。入射角度对太赫兹波的反射特性具有一定的影响，但整体影响不大，有利于太赫兹波实现多角度目标的探测。最后，以表面均匀涂覆0.42 mm厚涂料的金属板为测试样品，实验测量了样品在0.1~1.5 THz频率范围内的反射特性，并与部分理论计算结果进行对比。结果表明：实验测量结果与理论计算结果在数值和趋势上较为吻合，但也存在一定的偏差。究其原因，主要由样品厚度和样品参数误差导致，但依然可利用特征矩阵理论研究红外低发射率涂层对太赫兹波的反射光谱特性。

Reflection Spectrum Study of THz Wave by Infrared Low Emissivity Stealth Coating

In order to study the reflection characteristics of infrared low emissivity camouflage coating in Terahertz(THz) wave, the coating was prepared and its characteristic parameters such as visible image, infrared thermal image and infrared emissivity were tested. The complex refractive index of khaki-yellow infrared low emissivity coating in THz band was obtained by using the transmission THz time domain system. The characteristic matrix theory was analyzed, which was used to calculate the reflection spectrum of the coating in THz wave carried by the change of coating thickness(0.3~0.5mm) and incident angle(0°~60°) respectively. The results show that THz wave has multiple reflection peaks below 0.8 THz, and the maximum value is more than 90%. The result shows that the detection to metal targets that are coated by the infrared low emissivity camouflage coating by applying THz wave is meaningful. In addition, the thickness change of the coating has a great influence on the reflectivity of incident terahertz wave. The thicker the coating, the more reflection oscillation the THz wave has and the greater reflection peak value of it.The incident angle has a certain influence on the reflection characteristics of THz wave, but the overall effect is small, which is beneficial to the detection of multi-angle target by THz wave. Finally, the reflection characteristics of the metal plate coated with 0.42 mm thickness coating in 0.1~1.5 THz were measured, and the experimental results were compared with partial theoretical calculation results. The results demonstrate that the experimental results are in good agreement with the theoretical results, but there are also some deviations. The reason is mainly caused by sample thickness and sample parameter error, but the characteristic matrix theory still can be used to study the reflection spectrum of THz wave by infrared low emissivity stealth coating.