微波传输线中导体粗糙表面轮廓影响的精确建模

项目名称： 微波传输线中导体粗糙表面轮廓影响的精确建模

项目编号： No.61471293

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 黄斌科

作者单位： 西安交通大学

项目金额： 80万元

中文摘要： 在微波器件小型化趋势下，随着信号带宽或数字速率的持续增大，导体粗糙表面成为影响微波器件工作性能的重要因素。在高频段时粗糙表面影响趋于显著，传统方法的预估结果和实际器件的电性能相比误差较大；而采用实验测试方法时周期长、成本高。本项目以微带线和闭域波导为模型，考虑导体粗糙表面轮廓，研究多尺度结构共存时Maxwell方程的数值求解问题。采用自适应导体细线模型，混合隐式显式时域有限差分方法和闭域有耗边界条件下的电磁场积分方程实现大尺度微波传输结构建模，采用周期结构和有耗介质材料层等效实现小尺度粗糙导体边界表征。采用微分外推方法提取分离导体粗糙表面对微波传输线电特性的影响关系，并建立导体粗糙表面轮廓对微波传输线电特性参数的影响规律及光滑等效修正关系。导体粗糙表面的精确建模在提高微波电路性能指标、实现PCB板介质材料参数宽带建模、提高空间微波器件工作可靠性和拓宽微波测量仪器量程等问题中具有应用价值。

中文关键词： 微带线；波导；传输特性

英文摘要： Nowadays in the trend toward miniaturization of microwave components, conductor surface roughness has significant effects on the signal degradation over the wide frequency range from tens of Megahertz to 20+ GHz, or for data rates above 10+Gb/s. Often conductor surface roughness is accounted for using correction factor from the well-known Hammerstad-Bekkadal equation. With a much rougher surface, the equation saturates at high frequencies, which leads to an significant error compared to the performance from the actual components . However, the approach of measurement is expensive and time consuming since plenty of samples must be fabricated and measured in extracting the effect of conductor surface roughness. As typical microwave transmission line with broad applications, microstrip and waveguide are used to characterize the effect of conductor surface roughness. The project has two main challenges. Firstly, considering the boundary of conductor surface roughness, the numerical method should be investigated about co-simulating of multiscale structures in solving Maxwell equations; Secondly, the rules of the electrical performance of the microwave transmission with the conductor rough surface are extracted with the results from the numerical simulations. The adapted filament model in frequency domain, hybrid implicit-explicit finite difference time domain method and electromagnetic field integral equations with lossy conductor boundary in closed domain are adopted to modeling the microwave transmission lines with large scales; To modeling the conductor surface roughness in small scales accurately and efficiently in numerical simulation, the period boundary condition from a geometrical view and a layer with an effective lossy dielectric material from a material view are studied. The accurate of the numerical methods are validated with measurements. Based on the simulation results from the numerical methods, the effect of the conductor surface roughness can be separated with the differential extrapolation method, then the modeling of the effect of conductor surface roughness on the electrical parameters of microwave transmission line can be derived. Finally, the physical explanation of the effects of the rough surface can be obtained, and the correction factors for the different electrical parameters of microwave transmission lines due to the surface roughness can be established. With the achievement of accurate modeling of conductor surface roughness, the performance parameters in planar microwave circuits can be modelled accurately, the information of PCB dielectric substrate materials can be characterized over a wide frequency range, the electromagnetic reliability and the age can be improved for the space microwave components, the measurement range of microwave instruments can be extended to more higher frequencies. In summary, the investigations of the project have more potential applications in varied engineering problems.

英文关键词： microstrip lines;waveguides;transmission characteristics