中文摘要：

如何灵活地控制和操纵太赫波是目前研究的热点.根据电磁波传输理论,导出了等离子体辅助平板波导的场分布和色散关系表达式,计算了其传输特性,并通过全波仿真进行了证实.结果表明,等离子体辅助平板波导具有带阻特性,上边带截止频率等于等离子体频率,等离子体层越薄,下边带截止频率越高,带宽越窄;阻带内存在两种不同的物理机理,一种与等离子体和中间媒质的谐振耦合有关,另一种与表面波的形成有关.此外,本文还研究了等离子体频率及碰撞频率对传输特性的影响,提出了通过改变等离子体频率调谐平板波导滤波器特性的方法.同时,采用褶皱金属结构实现了等离子体层,设计了平板波导传感模型,通过改变凹槽内的材料的介电常数仿真了其传感特性,结果表明当材料的介电常数变化0.1%时,平均截止频率变化1.8GHz;通过检测截止频率的变化,传感器能明显分辨氮、汽油、液态石蜡、甘油和水,证实了其优良的太赫传感特性.这项工作对研究太赫波的传输及太赫器件的设计和制备具有指导意义.

英文摘要：

Flexible control of terahertz waves is now a research hotspot. Based on the electromagnetic theory the dispersion relation and field distributions in a plasmon-assisted parallel-plated waveguide are deduced. The transmission property of such a waveguide is obtained and confirmed by the full-wave simulation. Results show that the plasmon-assisted parallel-plated waveguide shows a band gap characteristic, and the cutoff frequency of the upper sideband is equal to the plasmon frequency; generally, the thinner the plasmon layer, the higher the cutoff frequency will be, and the narrower the bandwidth will become. Emergence of the band gap is due to the excited surface plasmon polaritons, and the coupling between surface plasmon and the medium in the waveguide. Besides, the influence of plasmon frequency and collision frequency on the transmission properties is investigated, and a method for adjusting the filter characteristic of the waveguide by tuning the plasmon frequency is proposed. Moreover, the plasmon layer is realized by a textured metallic structure, and a sensing model based on the parallel-plated waveguide is designed. Simulation results show that a 0.1 percent change in permittivity of the sample materials filling in the groove will give rise to a significant change of the cutoff frequency, which is 1.8 GHz in average; interestingly, different liquid samples such as nitrogen, gasoline,paraffin, glycerine and water can be identified through detecting the change of cutoff frequency, which further confirms the excellent terahertz sensing characteristic of the proposed sensor. This work may be helpful for the study of terahertz wave transmission, and may have potential applications in the design of terahertz devices.