Analysis of Superconducting Microwave Transmission Lines (REU SUPPLEMENT)

在平面传输线中加入高温超导材料在高速数字和高频模拟应用中具有广阔的应用前景。在充分利用高温超导系统之前，需要评估它们的电流和功率处理能力。知道材料的临界电流密度并不能直接得出传输线所能承载的最大电流。在本次研究启动奖中，将使用伦敦方程和双流体模型来研究高温超导输电线路上的电流分布。它们将与两种电磁模型中的一种相结合。第一个是全波分析。利用有限差分格式将所建立的方程离散到二维网格结构截面上。在不超过材料临界电流密度的情况下，可以计算出高温超导微带线的总电流和总功率。由正常电子引起的损耗和q因子直接得到。我们已经进行了初步计算，初步结果非常令人鼓舞。我们在这里建议通过结合衬底损耗和非线性电导率来充分发展模型。然后，将充分开发的模型用于高温超导微带线的综合分析。制定微波超导平面传输线的设计准则。将对不同平面传输线进行比较研究，以选择能充分发挥高温超导性能的最佳结构。

Incorporating High Tc Superconducting (HTS) materials in planar transmission lines is very promising for high speed digital, and high frequency analog applications. Before full exploitation of the HTS's, their current and power handling capacities need to be assessed. Knowing the material critical current density does not directly lead to the maximum current that can be carried by the transmission line. In this Research Initiation Award, London's equations and the two-fluid model will be used to investigate the current distributions on HTS transmission lines. They will be coupled with one of two electromagnetic models. The first on is a full-wave analysis. The developed equations are discretized over the structure cross-section in a two dimensional mesh using the finite-difference scheme. The total current carried by an HTS microstrip line without exceeding the critical current density of the material as well as the total power can be calculated. The losses due to normal electrons and the Q-factor are directly obtained. We have already performed initial calculations, and the preliminary results are very encouraging. We here propose to fully develop the model by incorporating substrate losses and non-linear conductivity. Then, the fully developed models will be used for comprehensive analysis of HTS microstrip lines. Design guidelines for microwave superconducting planar transmission lines will be developed. Comparative study between different planar transmission lines will be performed to select the best structure that fully exploits HTS capabilities.