The Research Of Terahertz Band-stop Filter Based On Electronic Resonance Response

Electric-LC unit is an important type of frequency selective surface(FSS)unit,which has very important application value for building THz passive devices such as filters,absorber and modulator.As the developing of THz communication,radar and imaging technology,the research of wide-band and dual-resonance band-stop filters will become a trend.Thz band-stop filters based on ELC is studied in this paper.A new band-stop filter based on FELCCSL(four-split electric-LC with centric square loaded) and CDR-ELC(Compound dual-resonance ELC) are studied in this paper.The central frequency is 0.42 THz.The influence of resonance unit parameters and medium base electric parameters on filter frequency response is also studied.The result shows that,the introduction of inductant load makes four-split arm field coupling much stronger.The stopband resonance frequency and stopband bandwidth increase 25% and54.1% respectively than FELC structure.Dual-resonance FSS structure are more complex in both designing and engineering.A new dual-resonance band-stop filter based on CDR-ELC is studied in this paper.On the basis of two SR-ELC(Single-resonance ELC),we mix them together.Under the incident field excitation,the mixed structure have different surface circuit loop,results in different resonance frequency.The resonance property of SR-ELC and CDR-ELC are studied respectively in this paper by simulation,the influence of structure parameters on CDR-ELC structure frequency response is also analyzed.The simulation finds out that the first stopband filtering property of complex unit is obviously enhanced because of the coupling of two ELC unit,with bandwidth near tripled and the minimum transmission coefficient decreased by 1.2d B.The result shows the CDR-ELC band-stop filter has the advantage of wider bandwidth and lower transmittance,which provide a simple method for building dual-frequency THz band-stop filter.