The Research Of Terahertz Cavity Filter

The terahertz(THz) wave is the extremely high frequency electromagnetic radiation that range from 100 GHz to 10 THz. The spectrum of terahertz wave lies between millimeter wave and infrared,which brings THz many unique properties. The research and application of THz wave become more and more popular since we entered the twenty-first century. In every terahertz application system, frequency selection is an essential step to process the THz wave, so it is very valuable to design and fabricate efficient and reliable THz filter.In this thesis, the development tendency and the basic theory of designing, calculation were introduced. Then the summary of THz filter fabricating was made to decide which structure was suitable in this thesis. The 3D electromagnetic simulation model of cavity filters were established and the structure size was optimized in three key frequency windows of Terahertz atmospheric transportation. Rectangular resonant cavity and cylindrical resonant cavity structure are adopted in the filter fabrication. The experimental measurement was also carried out. The experiment demonstrated that the rectangular resonant cavity band-pass filters can operate at 220 GHz and 440 GHz respectively with insert loss better than 2dB and return loss better than 12 dB.The maximum insert loss of cylindrical resonant cavity filter operating at 340 GHz was 5dB. Meanwhile, the tolerance analysis of the filter was carried out, the influence of assembly was simulated and the 3D print THz filter was discussed in this paper.The achievements of this dissertation make a contribution to the development of design THz cavity filters and also lay a foundation for the further research and applications.