Researches Of Flexible Terahertz Functional Devices And Terahertz Planar Antennas Based On Artificial Microstructures

In recent years,the rapid developments of terahertz technology are closely related to the supports of terahertz functional devices.At the same time,terahertz functional devices play extremely important roles in improving the performances of terahertz systems.However,due to the limitations of traditional material properties and device structures,the performances of current THz functional devices are difficult to be further improved.The terahertz functional devices based on artificial microstructures provide new ways to realize high-performance terahertz devices and lay the foundation for the wide applications of terahertz technology.Therefore,a terahertz flexible wire-grid polarizer,a flexible petal-like band-stop filter and asymmetric planar bowtie antennas based on artificial microstructures were proposed and studied in this thesis,they can be applied in terahertz optical systems,communication systems and imaging systems.They also could extend the versatility of terahertz systems.The research contents of this thesis are as follows:1.A flexible ultra-thin optically transparent wire-grid terahertz polarizer based on indium tin oxide(ITO)was proposed,which used conductive ITO as wire-grid structure and flexible polyethylene terephthalate(PET)film as substrate.The proposed terahertz polarizer can not only control the terahertz wave polarization,but also provide high transmittance for visible and near-infrared radiation.Therefore,the device can satisfy the performance requirements of multispectral cooperation in terahertz systems.This work provides a new approach for the realization of highly flexible and optically transparent terahertz devices.2.A petal-like terahertz band-stop filter based on flexible ultra-thin polyimide(PI)was proposed,which used metal petal-like arrays as response resonant structure and PI film as substrate.The experiment result of the proposed terahertz band-stop filter had a good agreement with the simulation result.0.351 THz signal within 0-1.5 THz can be filtered by our filter,so the device can satisfy the versatility requirements of terahertz systems.This work provides a new way to realize high flexibility and wide expansibility of terahertz systems.3.An asymmetric metal bowtie antenna structure was proposed.The structure size optimization and polarization characteristics of the bowtie antennas were simulated and analyzed according to the field enhancement effect,and the fabrication process of asymmetric bowtie antennas is realized by the overlay process in the experiment.This work provides optimized idea of structure and fabrication process for the terahertz planar antennas with strong coupling performance.