【作者】 陈宏巍；

【导师】 房少军；

【作者基本信息】 大连海事大学 ， 通信与信息系统， 2014， 博士

【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。更多还原

【Abstract】 Coplanar waveguide, as a kind of important transmission line, has been implemented on microwave, millimeter wave, submilimeter wave, optics and high temperature superconducting integrated circuits, etc. even it has been applied in microwave circuits instead of microstrip, thus coplanar waveguide is occupying more important position in MMIC. The asymmetric coplanar waveguide is a novel transmission line developed from coplanar waveguide. Compared with coplanar waveguide, the slot widths of asymmetric coplanar waveguide are different, thus the asymmetric coplanar waveguide is a kind of extension of coplanar waveguide, and it has more generality and flexibility than coplanar waveguide.The asymmetric coplanar waveguide has been studied by many scholars, but the theory analysis and practical application are still at their stage of development for the limitation of the test condition and the application experience.In the theory analysis, asymmetric coplanar waveguide has been analyzed by many scholars using conformal mapping method, but the conformal mapping method can not be applied in frequency domain. Some scholars use the time domain methods, such as finite difference time domain method and multi-resolution time domain methods, to analyze the dispersion characteristics of the asymmetric coplanar waveguide, but the unique characteristics of the asymmetric coplanar waveguide cannot be found for the limited precision of these methods. This dissertation applies NPML boundary to2D finite difference frequency domain, then uses the new algorithm on the analysis of asymmetric coplanar waveguide. Compared with UPML finite difference frequency domain, NPML finite difference frequency domain is easy to implement by programming, and it is more suitable for open structure transmission line, such as microstrip line and asymmetric coplanar waveguide, etc. This dissertation has calculated the phase constant of the microstrip line, coplanar waveguide and asymmetric coplanar waveguide using2D finite difference frequency domain of NPML, and the asymmetric coplanar waveguide with via hole is analyzed for the first time through this algorithm. Because of the poor accuracy of finite difference frequency domain in the characteristic impedance calculation, the wave equation as interpolation function is added in the finite difference frequency domain to improve the accuracy of the algorithm.In the practical application, the study of discontinuous of asymmetric coplanar waveguide can not be overstepped. This dissertation mainly researches on asymmetric coplanar waveguide bend. First, the mode conversion of asymmetric coplanar waveguide is investigated through finite difference frequency domain and finite difference time domain. Second, through analyzing the mode conversion of three kinds of asymmetric coplanar waveguide and coplanar waveguide bends, it is noted that the energy conversion of asymmetric coplanar waveguide between modes is smaller compared with coplanar waveguide. That means the asymmetric coplanar waveguide bend can transmit signal better. Third, for verifying the low transmission loss of asymmetric coplanar waveguide, a new test fixing is proposed and designed by taking advantage of different field distribution of different modes. According to the characteristics of asymmetric coplanar waveguide, a novel coplanar waveguide is proposed by combining the transformation unit between asymmetric coplanar waveguide and coplanar waveguide. The experiment shows the novel coplanar waveguide bend restrain the energy conversion effectively, and it has low transmission loss.更多还原