利用聲子晶體探討共振腔波導與負折射現象

Abstract

本研究利用有限元素數值分析和實驗來驗證聲子晶體的負折射現象和濾波波導現象。在負折射部分利用有限元素套裝軟體模擬體聲波通過聲子晶體發生負折射的頻率和角度，並設計一組直徑6mm、填充率0.51，三角晶格排列共20x6的陣列來做模擬與實驗的驗證。而在濾波波導部分則利用聲子晶體內部不同形式的缺陷來討論濾波和波導的效果，首先我們利用有限元素軟體COMSOL計算出聲子晶體的頻溝區段，並在聲子晶體內製造不同的缺陷且分析這些缺陷對於濾波和波傳的影響，並設計一組直徑 6mm、填充率0.46，正方晶格排列之聲子晶體來做模擬與實驗的驗證，利用聲子晶體在以上的這些特性，未來我們可以製作出具有聲源聚焦、濾波和波傳功能…等之聲學元件，讓聲子晶體的應用更為多元。

In this study, finite element analysis and experimental verification were employed for the negative refraction, filtering and waveguide phenomenon in phononic crystals. The software COMSOL with bulk acoustic wave propagates through the phononic crystal was used to find out the frequency and incident angle for the occurrence of negative refraction.. A physical array of 20 x 6 triangular lattice, fill factor 0.51 , and 6mm diameter for each singular pillar was designed for experimental validation. The effectiveness of filtering and waveguide was investigated by using various forms of defects in phononic crystal.. First of all, we use COMSOL to calculate the band gap of the phononic crystals and analyze different types of defect in phononic crystals for the impact of filtering and wave propagation. A physical array of square lattice, fill factor 0.46 , and 6mm diameter for each singular pillar was designed for experimental validation.