The Transmission Properties Of THz Polymer Tube

As the application study of the terahertz (THz) technology in fields ofnondestructive biology testing, environmental monitoring and broadbandtelecommunications, etc, THz technology grows popular among the researchers.However, there can be huge restricts in practical application, due to the lack of lowloss and low dispersion waveguide; therefore, it promotes the THz application most ifthe study of high performance THz waveguide welcome into action-This is becausevapor absorption and atmospheric scattering can result in the THz energy loss to alarge scale in free transmission space. The thesis aims to analyzing the transmissioncharacteristics of THz polymer wave tube in the window from330GHz to380GHz.The thesis, firstly analyze the interaction between THz wave and objects-therefractive index and dielectric constant of the specific objects under the THz wave, andintroduce the basic theory of THz wave transmission, especially laying focus onattenuation and dispersion of it. Secondly, doing studing on the transmissionperformance of noncoating THz waveguide tube with HFSS software, whichintroduces some basic performance parameters to this kind of tube and making acomparison to metal and polymer tube-the results show that the THz does better thanthe metal one，however, the existence of mimicking surface plasmas phenomenon inthe THz polymer waveguide tube has prevented its transmission performance fromachieving ideal. Thirdly, coating the tube, including inner wall coating, outer wallcoating, inner and outer wall coating and on this basis researching its transmissionperformance, which shows that although coating can effectively suppress thephenomenon of mimicking surface plasmons in THz polymer waveguide, but theintensity of field distribution is weak. After coating, it comes into the grooving-theaxial grooving (one, two, three and four crevices) and radial grooving (circular andspiral one). The results show that grooving inhibited mimicking surface plasmaphenomenon, enhance the intensity of field, and easily controlled its transmissioncharacteristics. Finally, THz non-coating and inner coating Teflon tube were made,and their loss and dispersion were tested under THz time-domain spectrometer, and thecauses of error were also analyzed.In conclusion, the transmission of THz wave in the polymer tube after coating andgrooving can gain lower the energy loss and achieve the requirements in the wirelesscommunication system, and applying to the field of THz communication, which makespositive influence to the study of THz polymer waveguide.