共查询到20条相似文献,搜索用时 171 毫秒
1.
研究了太赫兹波在透射波窗口封闭的激波管中的等离子体中的传输特性,获得了传输衰减量随等离子体电子密度、碰撞频率、透波窗口材料以及电磁波频率的变化规律,并比较了相同条件下毫米波的传输特性.利用激波管为实验平台模拟产生高速飞行器等离子体,开展了太赫兹波在等离子体中传输特性实验.结果表明,太赫兹波在相同电子密度和碰撞频率的等离子体中衰减量比毫米波小得多;随着等离子体碰撞频率的增加,太赫兹波传输衰减量先增加后减小,透波窗口增加了太赫兹波的传输衰减;随着窗口材料的介电常数增加,太赫兹波反射率增加,太赫兹波传输衰减曲线出现周期性振荡,振荡周期约5 GHz;太赫兹波通信可能作为一种解决再入飞行器黑障问题的有效技术途径. 相似文献
2.
3.
4.
5.
6.
设计了一种具有良好传输特性的太赫兹聚合物管。利用HFSS仿真分析太赫兹聚合物管的传输特性,其S参数较为理想,传输损耗小且传输系数大于0.96。但是太赫兹聚合物管的场分布中存在仿表面等离子体现象,这会使太赫兹聚合物管的传输特性劣化。进而,采用三种不同的镀膜方式对太赫兹聚合物管镀金属膜,发现镀膜可以有效抑制太赫兹聚合物管场分布的仿表面等离子体现象,使场分布更均匀、更稳定。并且,对比这三种镀膜方式发现内壁镀膜时太赫兹聚合物管的传输特性最优,而内外镀膜时最差。因此,太赫兹聚合物管镀膜宜优先选用内壁镀膜,可以简化工艺和降低成本。 相似文献
7.
太赫兹纤维波导是太赫兹系统中重要的组成元件。为了实现太赫兹辐射的低损耗低色散传输,设计了一种以环烯烃共聚物为基质的多孔太赫兹纤维,并利用基于全矢量有限元法的商业软件COMSOL 分析了该多孔太赫兹纤维的传输特性,着重考察了亚波长多孔纤芯的结构参数对传输特性的影响。结果表明,这种太赫兹纤维可以将模场能量很好地限制在亚波长多孔纤芯中传输,具有较小的有效模场面积、低的传输损耗和平坦近零色散等优良的传输特性;同时,通过增大多孔纤芯的占空比,可以将更多的模场能量限制在亚波长直径的空气孔洞中传输,并减小太赫兹纤维的有效模场面积和有效模式损耗,但同时会增大限制损耗和色散。 相似文献
8.
太赫兹纤维波导是太赫兹系统中重要的组成元件。为了实现太赫兹辐射的低损耗低色散传输,设计了一种以环烯烃共聚物为基质的多孔太赫兹纤维,并利用基于全矢量有限元法的商业软件COMSOL分析了该多孔太赫兹纤维的传输特性,着重考察了亚波长多孔纤芯的结构参数对传输特性的影响。结果表明:这种太赫兹纤维可以将模场能量很好的限制在亚波长多孔纤芯中传输,具有较小的有效模场面积、低的传输损耗和平坦近零色散等优良的传输特性;同时,通过增大多孔纤芯的占空比,可以将更多的模场能量限制在亚波长直径的空气孔洞中传输,并减小太赫兹纤维的有效模场面积和有效模式损耗,但同时会增大限制损耗和色散。 相似文献
9.
计算了螺旋槽波导的色散特性和群速度,用“准周期边界条件”方法和谐振法模拟计算了螺旋槽波导的色散特性,两种方法的模拟结果与计算都比较一致。此外,还模拟测试了渐变与规则螺旋槽波导连接的匹配性能、螺旋槽波导高频系统的传输特性。结果表明,螺旋槽波导是非常适用于回旋行波管的高频结构。 相似文献
10.
研究了太赫兹波垂直通过具有周期性亚波长环形空气槽阵列的金属-介质-金属三层结构的透射谱特性,以及与表面等离子体谐振的关系。共振模式电场分布与色散曲线分别表明:表面等离子体具有束缚性,表面电磁波的传输机制与能量流动过程,透射谱的两个共振峰与传播性的表面等离子体模式、局域化的表面等离子体模式及其耦合有关。改变结构的几何参数,其共振峰变化趋势进一步印证了以上观点,并且空气环中激发的准波导效应也影响了太赫兹波的传输。 相似文献
11.
太赫兹波具有良好的穿透性、低能性和宽带性,在高速空间通信、环境监测、外差探测、医学探测、无损检测和国防安全等领域具有重要的应用前景。波导传输技术和功能器件是太赫兹系统不可或缺的重要组成部分,太赫兹波导的性能决定了太赫兹系统的信号传输效率和集成度,引起人们的研究兴趣。近年来,太赫兹波导的发展取得了长足的进步,从普通的金属空心波导到金属线波导、介质光纤,再到最近的人工表面等离激元波导、石墨烯、铌酸锂等新型波导,它们展现出了各自的优势,令人振奋。该综述全面介绍了太赫兹波导领域的发展及研究近况,并对其未来应用进行了展望。 相似文献
12.
利用太赫兹时域光谱系统对三种反谐振波导的太赫兹谱进行了研究, 这三种波导分别是PMMA管型波导, PMMA自支撑结构波导和SiO2管型波导.该研究验证了三种波导的太赫兹传输基于反谐振理论, 并在实验上实现了PMMA自支撑结构波导超过2 THz的宽光谱传输.同时, 对基于反谐振原理的太赫兹物质传感进行了理论和实验分析, 为物质探测提供了一种可行的手段. 相似文献
13.
14.
15.
Zhihui Wang Yong Zhang Ruimin Xu Weigan Lin 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(2):204-215
In this paper, a shielded dielectric multiple-slot waveguide is presented and demonstrated by theoretical calculation at terahertz
frequencies. Some electromagnetic analysis of waveguide currently employed simplified intrinsic frequency dispersion models
for the bulk conductivity of normal metals used in terahertz wave structures. This paper has compared various conductivity
models for gold between 0.1-3 THz. The dielectric loss, conductor loss, total propagation loss with different conductivity
models and E-field distribution has been obtained by numerically solving the complex eigenvalue equation for the propagation
constant. The analysis results are in agreement with the assumption of R. Sun et al. and the experimental results obtained by H. Sun et al. The propagation loss deviation between various models is less than 3% at 0.2-0.5 THz. Comparisons with other slot waveguides
are also given. The analysis results show that the proposed line has lower propagation attenuation than other slot waveguides. 相似文献
16.
利用有效折射率法(EIM)理论设计了有机聚合物脊形光波导结构,并分析光波导中传输的模式场,确定出光波导结构的适宜尺寸范围。光波导结构中分别选用PMMA(聚甲基丙烯酸甲酯)与PDMS(聚二甲基硅氧烷)作为波导层与包层的材料,用光漂白法来实现脊形波导结构。首先利用EIM法分析脊形波导区的宽度与高度之间的关系对归一化色散曲线的影响,以及波导层与包层的折射率匹配的影响,然后又通过分析波导区传输的基模场来讨论传输的损耗问题。研究发现波导结构的脊宽与脊高之比w/d越大,其有效折射率neff越大,而此结构尺寸又需约束在一定范围内,否则将造成很大的传输损耗。 相似文献
17.
Dominik Walter Vogt Rainer Leonhardt 《Journal of Infrared, Millimeter and Terahertz Waves》2016,37(11):1086-1095
We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β 2 of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide. 相似文献
18.
Network analyses for transmission characteristics of several kinds of curve-shaped groove waveguides
Fuyong Xu Keyu Zhao Ling Zhao 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(10):1789-1798
In this paper, the several kinds of the novel curve-shaped groove guides including the whole elliptic-, whole cosine- and hyperbolic-groove guides as the new millimeter wave transmission lines are presented. The dispersion, cut-off and band characteristics of the dominant mode for the several kinds of the curve-shaped groove guides are analysed by using the equivalent network method with transverse resonance. The obtained results have important values in their theoretical studies and actual applications of the curve-shaped groove waveguides. 相似文献
19.
Fuyong Xu Keyu Zhao Ling Zhao 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(6):1307-1315
An advantage of closed groove guide over open groove guide is attended. In this paper, the several kinds of closed groove guides including the trapezoidal-, elliptic- and parabolic-groove guides as new types of millimeter wave transmission lines are presented. Their dispersion and cut-off characteristics of the dominant mode are analysed and compared with ones of the closed V-and circular- groove guides by using the equivalent network method. The obtained results have important meaning in theoretical studies and actual applications of groove waveguides. 相似文献
20.
Based on the mode-matching procedure, a unified transverse scattering matrix formulation is presented for the characterization of a class of waveguide eigenvalue problems, which include not only closed but also open structures. As examples, calculations are carried out on the dispersion characteristics of ridged waveguides and their variations, nonradiative dielectric (NRD) waveguides, groove guides, microstrip lines, finlines and coplanar waveguides. Comparisons with published data are made and verify the versatility and accuracy of the method. Besides its generality, this approach is also superior to some other techniques in simplicity and numerical efficiency 相似文献