Design and Analysis of Frequency-Selective Surface Enabled Microbolometers
Frequency Selective Surfaces (FSS) are periodic array of sub-wavelength antenna elements. They allow the absorptance and reflectance of a surface to be engineered with respect to wavelength, polarization and angle-of-incidence. This paper applies this technique to microbolometers for uncooled infrared sensing applications. Both narrowband and broadband near perfect absorbing surfaces are synthesized and applied engineer the response of microbolometers. The paper focuses on simple FSS geometries (hexagonal close packed disk arrays) that can be fabricated using conventional lithographic tools for use at thermal infrared wavelengths (feature sizes > 1 μm). The affects of geometry and material selection for this geometry is described in detail. In the microbolometer application, the FSS controls the absorption rather than a conventional Fabry-Perot cavity and this permits an improved thermal design. A coupled full wave electromagnetic/transient thermal model of the entire microbolometer is presented and analyzed using the finite element method. The absence of the cavity also permits more flexibility in the design of the support arms/contacts. This combined modeling permits prediction of the overall device sensitivity, time-constant and the specific detectivity.
T. Liu et al., "Design and Analysis of Frequency-Selective Surface Enabled Microbolometers," Proceedings of SPIE, Infrared Technology and Applications XLII (2016, Baltimore, MD), vol. 9819, SPIE, Apr 2016.
The definitive version is available at https://doi.org/10.1117/12.2224271
SPIE Defense + Security (2016: Apr. 18-21, Baltimore, MD)
Mechanical and Aerospace Engineering
Intelligent Systems Center
Keywords and Phrases
Bolometers; Electromagnetic wave absorption; Electromagnetic wave polarization; Fabry-Perot interferometers; Frequency selective surfaces; Geometry; Infrared radiation; Temperature sensors; Frequency selective surface (FSS); Hexagonal close packed; Metasurface; Microbolometer; Perfect absorber; Specific detectivity; Spectral selectivity; Sub-wavelength antennas; Finite element method
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