Frequency selective surface-based terahertz broadband band-pass filter

Abstract

The invention discloses a frequency selective surface-based terahertz broadband band-pass filter. The filter comprises a frequency selective surface layer which is of a single layer structure; the outer surface of the frequency selective surface layer is made from a metal material; multiple through holes are formed in the frequency selective surface layer, and arranged in the frequency selective surface layer at equal intervals, a periodic through hole array is formed, and frequency-selecting is conducted on a terahertz wave through coupling of the terahertz wave and the periodic through holearray. The terahertz broadband band-pass filter has the single-layer frequency selective surface structure of a porous structure, the in-band pass rate is high, the structure is simple, and the processing difficulty is greatly lowered; polarized light x and polarized light y have the same band-pass filter property, and the polarization insensitivity is achieved; due to the fact that the size and thickness of a periodic unit are large, laser drilling and other technologies can be adopted for completion, and the processing speed is high.

Description

technical field [0001] The present invention relates to the technical field of terahertz filters, in particular to a terahertz broadband bandpass filter based on a frequency selective surface. Background technique [0002] Terahertz (THz) waves generally refer to electromagnetic waves with a frequency of 0.3 to 3 THz (or a wavelength of 0.1 to 1 mm). Terahertz waves have important research value and application prospects in basic research disciplines such as physics, chemistry, and life sciences, as well as applied disciplines such as medical imaging, security inspection, product testing, space communication, and weapons guidance. It is difficult for conventional materials to generate electromagnetic responses, especially magnetic responses, in the terahertz band, and there are many blank spots in scientific research and technical applications in the terahertz band. Artificial electromagnetic materials can break through the limitations of the degree of freedom in changing t...

AI Technical Summary

Problems solved by technology

The frequency selective surface filter with a single-layer structure is relatively easy to achieve filtering performance, but the frequency range corresponding to the bandpass or bandstop is often very narrow

The FSS cascade with multi-layer metal hole structure can realize the band-pass filter characteristics of flat top and steep cut-off, but this structure has great difficulty in adjusting the distance between layers, and there are great difficulties in processing: on the one hand, The pattern of the metal structure on the surface of the multi-layer frequency selection is the same, and it needs to be aligned during processing. If the medium is opaque, it is difficult to completely align the two-layer metal structure, which will affect the performance of the filter; on the other hand, because the terahertz band requires a thinner medium , usually hundreds of microns or even smaller, so it is easy to break the medium when making frequency selective surface structure patterns on both sides of the medium

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