超材料是具有亞波長尺度的人造結構，常以符合完美固態晶體的重複模式排列，且可表現出自然界中沒有的獨特物理特性，其中一個重要的特性便是它可以光學上展現負折射特性與電磁波吸收特性。通過改變人工設計的結構幾何參數，可以間接改變超材料的介電常數(ε)和磁導率(μ)以達到理想值，甚至使其變為負值。本研究主要在探討三角晶格水基超材料的吸收特性，水基超材料為以水作為主要材料之超材料，選擇使用水是由於水的介電常數較高、容易取得、成本較低，且其對環境的汙染也較小的原因。本研究對水滴所作的幾何設計分為三個主要構型，第一個構型是現存文獻之水滴陣列超材料，第二構型利用PLA作為乘載水的容器，並雕刻出三角晶格形狀之凹槽以容納水，使水之形狀變為此雕刻出之三角晶格形，第三構型為基於第二構型之結構再加上FSS頻率選擇層，結構由上至下分別為玻璃蓋、有溝槽之PLA容器、水、FSS頻率選擇層、玻璃板以及PEC。本研究預測了不同幾何參數下水基超材料的吸收率、反射率和透射率，探討之電磁波範圍為6~20 GHz，進行之參數分析包含不同水滴形狀與不同參數等的數值模擬，並找出能使水基超材料達到寬頻高吸收率之幾何結構。

In this study, the different geometry and combination of water-based metamaterials are simulated. The geometry of water-based metamaterials was mainly divided into three main structure. The first structure of metamaterial is the water droplet metamaterial extended from the literature. The second structure use PLA engraves a triangular lattice shape for carrying water as a container. The groove is used to carry water, so that the shape of the water becomes the engraved triangular lattice shape. The third structure is the structure based on the second structure plus the FSS frequency selective layer. The structure from top to bottom is glass, grooved PLA container, water, frequency selective layer, glass plate and PEC. By using the radio frequency model, the absorptivity, reflectivity and transmissivity of water-based metamaterials under different geometric parameters are predicted. The range of electromagnetic wave is 6-20 GHz. The parameter analysis includes different water droplet shapes, different size of unit cell of metamaterials and different combination of unit cell of metamaterials. The purpose of this study is to find out the geometric structure that can make water-based metamaterials achieve broadband high absorption rate.

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