从光学角度出发，首先讨论了单层VO_x 微测辐射热计中探测单元衬底上的金属反射镜的厚度以及材料对微测辐射热计红外吸收率的影响，利用软件建立了微测辐射热计的红外辐射吸收率模型，得到了厚度不同的Al 反射镜对微测辐射热计模型8～14 μm 红外波段吸收率的影响以及厚度为0.1 μm的3 种不同材质的金属反射镜对同一模型红外吸收率的影响。当厚度等其他参数相同时，使用Al、Copper 和Gold 用作金属反射镜的材料，单层_x 微测辐射热计模型在8～14 μm 波段的红外吸收率并没有明显区别。另外，我们改进了一种已有的_x微测辐射热计结构并对比了改进前后模型8～14 μm 红外波段的吸收率，改进后的模型平均吸收率达到了94%大于改进前初始模型的90%左右。最后，我们讨论了真空谐振腔高度与微测辐射热计桥面材料厚度对工作波段吸收率峰值处波长的影响。

In this paper, the effect of material and thickness of a metal reflector above a silicon substrate on the infrared (IR) absorptivity of a single membrane _x microbolometer (MBM) was discussed and an IR absorption model of a MBM using MATLAB and COMSOL finite element analysis software was constructed. The effects of Al, Cu and Au reflectors with a thickness of 0.1 μm on IR absorptivity were recorded, and results showed matching models for each metal reflector. The relationship between IR absorptivity and thickness of Al micro-reflector in _x MBM in the 8-14 μm wavelength range was also found. Results showed that when only the texture of the reflector material was changed, a _x MBM model with Al, Cu and Au reflectors had no clear distinction on IR absorption in the 8-14 μm wavelength range. The _x MBM model was then improved and compared to the 8-14 μm wavelength IR absorption spectra of an advanced structure model. The improved model obtained a 94% average absorptivity which was higher than that of the initial model which obtained a 90% average absorptivity. Finally, the relationship between vacuum cavity height, thickness of membrane and the wavelength with a peak absorptivity within the 8-14 μm band was discussed.