基于有限差分法的非对称共面波导及其弯曲结构的研究

发布时间：2018-06-28 17:09

本文选题：非对称共面波导 + 二维频域有限差分　；参考：《大连海事大学》2014年博士论文

【摘要】：共面波导作为一种重要的平面传输线,已应用于微波、毫米波、亚毫米波、光学和高温超导集成电路等领域,并已在一些电路中取代微带线,在微波集成电路中占据着越来越重要的地位。非对称共面波导是在共面波导的基础上发展而成的一种新型传输线。相比共面波导,非对称共面波导中心导带与两侧接地板之间的缝隙宽度是不同的,可以认为是共面波导的一种推广,更具有一般性和应用灵活性。虽然对非对称共面波导的研究进行了很多年了,但由于测试条件和实际应用经验限制,对于非对称共面波导的理论分析和实际应用研究仍处于发展阶段。为了对非对称共面波导进行理论分析,许多学者采用准静态的保角变换方法来进行研究,但保角变换方法难以分析非对称共面波导的频域特性。虽然时域的方法(如时域有限差分或时域多分辨率分析)能分析非对称共面波导的色散特性,但是由于受到精度所限,不能展现出非对称共面波导的优点。本文在前期研究的基础上,将近似完全匹配层边界应用于二维频域有限差分方法,使算法更加容易编程实现,更加适合分析开放结构的非对称共面波导传输线。应用改进后的二维频域有限差分方法对具有过孔的非对称共面波导相位常数进行了分析。由于直接应用二维频域有限差分方法计算传输线特性阻抗精度较差,提出了以一维波方程为插值函数的阻抗计算方法,提高了特性阻抗的计算精度。分析结果表明,非对称共面波导具有比共面波导更优的阻抗频域特性。不连续结构(如弯曲结构,十字节等)是非对称共面波导在实际应用时不可避免的电路形式,因此详细研究了非对称共面波导弯曲结构。本文将频域有限差分方法和时域有限差分方法相结合,对非对称共面波导弯曲结构的模式转换特性进行了分析。通过分析比较直角、45。斜角和圆角三种不同的共面波导和非对称共面波导弯曲结构,确定了非对称共面波导弯曲结构的模式间能量转换更小,这就意味着非对称共面波导比共面波导具有更低的传输损耗。为了验证这一结论,本文利用非对称共面波导上c模和π模具有不同的场分布特性,设计了一种测试装置并实际测试了各种弯曲结构的传输特性。基于以上研究,本文最后提出了一种新型的共面波导弯曲结构,实验结果表明了这种新型的共面波导弯曲结构抑制了模式间能量转换,具有更小的传输损耗。
[Abstract]:As an important planar transmission line, coplanar waveguide has been used in microwave, millimeter wave, sub-millimeter wave, optical and high-temperature superconducting integrated circuit, and has been used to replace microstrip line in some circuits. Microwave integrated circuits play a more and more important role. Asymmetric coplanar waveguide is a new transmission line based on coplanar waveguide. Compared with the coplanar waveguide, the gap width between the central conduction band of the asymmetric coplanar waveguide and the two sides of the floor is different, which can be considered as a generalization of the coplanar waveguide and more general and flexible in application. Although the research on asymmetric coplanar waveguide has been carried out for many years, the theoretical analysis and practical application of asymmetric coplanar waveguide are still in the developing stage due to the limitation of testing conditions and practical application experience. For the theoretical analysis of asymmetric coplanar waveguides, many scholars use quasi-static conformal transformation method to study, but the conformal transformation method is difficult to analyze the frequency domain characteristics of asymmetric coplanar waveguides. Although time-domain methods (such as finite-difference time-domain or multi-resolution time-domain analysis) can analyze the dispersion characteristics of asymmetric coplanar waveguides, they cannot show the advantages of asymmetric coplanar waveguides due to their limited accuracy. On the basis of previous studies, this paper applies the approximate perfectly matched layer boundary to the 2-D finite-difference method in frequency domain, which makes the algorithm easier to program and more suitable for the analysis of asymmetric coplanar waveguide transmission lines with open structure. The phase constants of asymmetric coplanar waveguides with holes are analyzed by using the improved two-dimensional finite-difference method in frequency domain. Due to the poor precision of calculating the characteristic impedance of transmission line by using the 2-D finite difference method in frequency domain directly, an impedance calculation method with one-dimensional wave equation as the interpolation function is proposed, which improves the calculation accuracy of the characteristic impedance. The results show that asymmetric coplanar waveguides have better impedance frequency domain characteristics than coplanar waveguides. Discontinuous structure (such as bending structure, cross section, etc.) is the inevitable circuit form of asymmetric coplanar waveguide in practical application, so the bending structure of asymmetric coplanar waveguide is studied in detail. In this paper, the frequency domain finite difference method and the time domain finite difference method are combined to analyze the mode conversion characteristics of asymmetric coplanar waveguide bending structure. Through the analysis and comparison of the right angle 45. Three different bending structures of coplanar waveguide and asymmetric coplanar waveguide with oblique angle and circular angle are obtained. It is determined that the energy conversion between modes of the bending structure of asymmetric coplanar waveguide is smaller than that of unsymmetrical coplanar waveguide. This means that asymmetric coplanar waveguides have lower transmission losses than coplanar waveguides. In order to verify this conclusion, a testing device is designed and the transmission characteristics of various bending structures are tested by using the different field distribution characteristics of c mode and 蟺 mode on asymmetric coplanar waveguide. Based on the above research, a new kind of coplanar waveguide bending structure is proposed in this paper. The experimental results show that the new coplanar waveguide bending structure can suppress the energy conversion between modes and have a lower transmission loss.
【学位授予单位】：大连海事大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN814

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