Simulationg And Designing Of Frequency Selective Surfaces For High Sensitivity Terahertz Sensing

The terahertz spectral detection technology can analyze and identify subtle changes in composition of the sample rapidly, but for small amounts substances, the sensing wavelength(hundreds of microns) has a great difference with the measured object size (nanometer),the sensitivity of the terahertz spectral detection technology will decline. Frequency selective surfaces are two-dimensional periodic array structures, which are composed of the periodic arrangement of metal sheets or gap units,the resonance peak of the frequency response curve will be drift by the change of the loaded medium, so it can be applied to the terahertz spectral detection technology to improve the sensitivity of the measurement of small amounts substances.The purpose of this paper is improving the measurement’s sensitivity of small amounts with THz waves, designing the split-ring unit FSS structure based on circular ring unit, square ring unit and hexagon ring unit, respectively. Researching the effects of the FSS’s unit forms, structural parameters and arrangement for the frequency response characteristics and the sensitivity of the terahertz spectral detection technology will be researched, analyzing the physical mechanisms based on variation and designing high-sensitivity terahertz sensors based on FSS.The results showed:for the three units, when the sample covering area is1/64of the units area,the sensitivity is highest.