基於低頻表面電漿極化子的漏波天線與微帶傳輸線

Abstract

在本論文裡，我們研究低頻表面電漿極化子(spoof surface plasmon polaritons， spoof SPPs)的特性，並將這個概念直接應用於波導以及微帶線上，對其傳輸特性進行理論與實驗的分析。 本論文的主要研究如下： 1. 表面電漿波導： 我們提出一種基於低頻表面電漿極化子的高指向性輻射的新型波導結構，而這個高指向性的輻射場來自於波導結構的漏波模式。 這個波導結構是由一維陣列金屬磚塊結構所構成。 每一個金屬磚塊結構在其頂部存在開口凹槽以及附加雙耳，金屬磚塊陣列結構則按亞波長的方式排列而成(其週期間格遠小於波長)。 這個波導結構的數值分析結果顯示，藉由在金屬磚塊上加入挖空的溝槽，將可以引入新的低頻表面電漿極化子模式而這樣的模式主要集中在凹槽區。 並且其色散具有負的折射率，並且新的傳輸模式的色散曲線將會在較高的頻率時穿過光的傳播線的色散曲線，並進入輻射區，形成漏波模式。 實驗將對波導在微波頻段時的傳輸與漏波進行測量，其實驗結果與理論預測極為一致。 2. 基於低頻表面電漿的微帶傳輸線： 我們提出基於低頻表面電漿極化子的抗串擾的新型微帶傳輸線結構，藉由理論及實驗分析顯示，這種微帶結構的抗串擾強弱取決於微帶傳輸線的自感與模式傳播的相速度。 這類傳輸低頻表面電漿極化子的微帶傳輸線是由在傳統微帶線的邊緣引入亞波長週期波紋結構所構成。 亞波長週期微帶傳輸線結構的數值分析結果顯示，藉由在微帶傳輸線上加入挖空的凹槽，將可以引入新的低頻表面電漿極化子模式而這樣的模式的電磁場可以有的約束於微帶結構的下面。 採用數值方法所獲得的S參數可以用等效電路模型來萃取新型微帶線結構的等效電感與電容及與傳統微帶線間的耦合電容及互感。 利用網路分析儀將對亞波長週期微帶線結構測量S參數，其實驗結果顯示與理論預測極為一致。In this work, based on the use of the concept of spoof surface plasmon polaritons (spoof SPPs). It applies the concept to waveguide structure and microstrip line, and the transmission characteristics of numerical and experimental analysis. The important results of this paper as the followings： 1. Surface plasma waveguide： We propose a new type of waveguide structure with high directivity radiation based on low frequency surface plasmon polaritons, and this high directivity of the radiation field from the waveguide structure of the leakage wave mode. The waveguide structure is composed of a one-dimensional array of metal block. Each metal block structure has an open slot at its top and an additional ear, metal block array structure is arranged in a subwavelength manner(The period lattice is much smaller than the wavelength). Numerical analysis of waveguide structure shows that by adding a open slots on the metal block, a new spoof surface plasmon polaritons mode can be introduced and such a mode is mainly concentrated in the groove region. Its dispersion curve has a negative refractive index, and the new transmission mode of the dispersion curve will be at a higher frequency through the light line, and going into a zone of radiation and forming of leakage wave mode. Experimental verification of such a leaky mode at microwave has been performed, and the experimental results are found to be consistent with the theoretical analysis. 2. Based on Microstrip Transmission Line of spoof surface plasmon polaritons： We propose a novel microstrip transmission line structure based on low frequency surface plasmon polaritons, which is based on theoretical and experimental analysis. The crosstalk strength of this microstrip structure depends on the self-inductance and mode propagation of the microstrip line itself Phase velocity. The microstrip lines of this type of spoof surface plasmon polaritons are formed by the introduction of subwavelength periodic corrugations at the edges of conventional microstrip lines. The numerical analysis of the subwavelength periodic microstrip line structure shows that by adding a groove to the microstrip line, it is possible to introduce a new spoof surface plasmon polaritons mode and the electromagnetic field of such a mode can be confined Under the microstrip structure. The S-parameter obtained by numerical method can use the equivalent circuit model to extract the equivalent inductance and capacitance of the new microstrip line structure and the coupling capacitance and mutual inductance. Using the network analyzer to measure the S-parameters of the sub-wavelength periodic microstrip line structure, the experimental results show that it is consistent with the theoretical prediction.