Design Of Terahertz Metamaterial

Metamaterial is a kind of artificial periodic structure or composite media with many novel properties absent in normal materials, whose electromagnetic characteristics are decided by electromagnetic characteristics of sub-wavelength structures and their spatial arrangement. Up to now, metamaterial provides more and more methods to design THz functional devices. This thesis is focus on the electromagnetic properties and applications of THz metamaterial, where the design, fabrication and experiment of THz metamaterial devices are discussed in detail. The main contents of this thesis are as follows:1. The basic concepts of THz metamaterial are introduced and the development and research of THz metamaterial is reviewed. The fabrication technology and experimental system of THz metamaterial are discussed in detail, including photolithographic process and terahertz time-domain spectroscopy(THz-TDS) system.2. A single-layer ultrathin broadband THz metamaterial absorbers is designed, fabricated and experimentally characterized. The advantages of designed THz metamaterial absorbers include thin depth, light weight, polarization and angle insensitivity.3. A ultrathin THz cross polarization converter based on metamaterial is designed and processing technology of free-standing THz metamaterial has been studied, experiment scheme of cross polarization transmittance is achieved by combination of transmission THz-TDS and THz wave plates.4. A low-scattering coding THz metasurface is designed based on the first-order iterative Minkowski fractal structure. Simulation and experimental results show excellent stealth performance, with broad bandwidth and satisfying angle insensitivity. Meanwhile, the low-scattering THz coding metasurface has advantages of ultrathin thickness, simple design flow and easy fabrication and so...