多層平面傳輸線的耦合結構以及波漏現象之分析

Abstract

本論文題目-「多層平面傳輸線的耦合結構以及波漏現象之分析」可以分 成兩部份。 在第一部份， 我們將研究共平面波導(coplanar waveuide) 主模(donminant mode)的波漏行為(leakage behavior)。對不同的幾何結 構， 波以表面波(surface wave)或平行板模(parallel-plate mode)的形 式漏掉。波漏現象會引起能量損耗，同時漏掉的能量傳輸經過線路會引起 交互失真(cross-talk)。如果有接地平面(ground plane)靠近共平面波導 的背面，將會有更嚴重的波漏現象。不管共平面波導有無靠近的導體，我 們的分析顯示一些有趣的物理現象，比如波漏現象(leakage)，尖銳和深 峻的極值(sharp and deep minima)，還有對不同尺寸的變化。在第二部 份， 我們將研究在雙層介電質(double-layer dielectric)中， 兩條半 無限長，共線(collinear)的微帶線(microstrip lines)，經由互相靠近 的開式端點(open-end)，波從一邊的微帶線入射進來將會耦合(couple)到 另一條微帶線去。 同時兩微帶線重疊的長度(overlap dis- tance)可以 用來控制耦合的效果。 動差法(method of moments)將被用來解積分方程 式(integral equations)。在公式中，格林函數(Green's function)將考 慮所有的物理效應， 其中包含了輻射和表面波漏(surface wave leakage)。 In this thesis the topic "coupling structures and surface wave/ parallel-plate mode leakage in mutlilayer planar transmission lines" can be devided into two parts. In part I, the leakage behavior of the dominant mode on coplanar waveguide (CPW) is studied. Depending on the particular geometry, wave leaks in the form of a surfave wave or parallel-plate mode. The leaked power propagating through a circuit results in undesirable cross-talk, and the leakage can cause a loss of energy from the guiding region. More serious leakage effect may occur if a ground plane is near the back of a CPW. An analysis of the properties of the CPW with or without a nearby conductor reveals some interesting physical phenomena, such as leakage, sharp and deep minima, and various dimension dependences. In part II, two semi-infinite collinear microstrip lines in double- layer are investigated. Through the proximate open-ends, wave incident from a microstrip line will be coupled to another one and the overlap distance can be used to contral the coupling. The method of moments is applied to the couplied integral equations. In the formulation, the Green's function will take into account all physical effects, including radiation and surface wave leakage.