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Experimental Studies on Sonic-Crystal Defect-Mode Waveguides Composed of a Periodic Chain of Single-Defects

单缺陷周期链组成的声晶体缺陷模波导的实验研究

基本信息

批准号：
18360176
负责人：
MIYASHITA Toyokatsu
金额：
$ 5.82万
依托单位：
Ryukoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

We have obtained the following results according to the purpose and plan of the research described in the application documents. In this report, a waveguide composed of a periodic chain of single-defects, or point-defects, are called a defect-mode waveguide.(1) Two methods to analyze the temporal and frequency characteristics of defects in an artificial crystal, namely, an internal excitation method which investigates them by exciting impulse, or burst sound pressure in a defect, and an external method by an excitation of a defect from the outside of the crystal.(2) Spatial confinement and frequency characteristics of a single-defect, or point-defect, embedded in a sonic crystal are investigated by both the external and internal methods, and the theoretical and experimental results had a good coincidence.(3) Temporal responses and frequency characteristics of two adjacent single-defects, which compose elementary parts of defect-mode waveguides, are investigated by FDTD simulations of t … More he wave propagation, by experimental external excitation method and by a coupled-mode theory. Well quantitatively agreed results indicated validity of the three methods.(4) Straight waveguides with and without a sharp bend composed of a chain of single defects proved to have a good 100% transmission in the pass-band by means of a FDTD simulation and an experimental external excitation.(5) Transmission characteristics of long defect-mode waveguides, which have a sharp bend and a branch or a crossroads, were measured by the ultrasonic waves of a frequency of 20〜40 kHz in air. The following items were confirmed, namely their high transmission per lattice constant in the pass band, and a high suppression in the forbidden band outside the pass band, and a good branching characteristics.(6) A high 50% mode coupling was obtained between a straight defect-mode waveguide and a neighboring defect-mode waveguide which has a sharp bend to remove from the former waveguide.(7) We have established a new coupled-mode theory which describes the behaviors of an arbitrary number of coupled modes of a chain of defect-modes. Quantitative preciseness of the results deduced by this theory was confirmed by the FDTD simulation and the experimental results described above. Less

根据申请文件中描述的研究目的和计划，我们获得了以下结果。在本报告中，由周期性的单缺陷链或点缺陷组成的波导被称为缺陷模波导。(1)分析人工晶体中缺陷的时间和频率特性的两种方法，即通过激励脉冲或缺陷中的突发声压来研究它们的内部激励方法，以及通过从晶体外部激励缺陷的外部方法。(2)用内外两种方法研究了声波晶体中单缺陷或点缺陷的空间限制和频率特性，理论和实验结果符合较好。(3)利用时域有限差分法（FDTD）模拟了缺陷模波导中两个相邻单缺陷的时域响应和频率特性，并与传统的时域有限差分法（FDTD）进行了比较 ...更多信息波的传播，实验外激励方法和耦合模理论。定量一致的结果表明，三种方法的有效性。(4)通过时域有限差分法（FDTD）模拟和实验外激励，证明了由一系列单一缺陷组成的直波导在通带内具有良好的100%透射率。(5)用频率为20 ~ 40 kHz的超声波在空气中测量了长缺陷模波导的传输特性，长缺陷模波导具有一个尖锐的弯曲和一个分支或十字路口。确认了以下项目，即它们在通带内的单位晶格常数的高透射率，以及在通带外的禁带中的高抑制，以及良好的分支特性。(6)在直缺陷模波导和相邻的缺陷模波导之间获得了高的50%模耦合，该缺陷模波导具有尖锐的弯曲以从前一波导移除。(7)我们建立了一个新的耦合模理论，它描述了缺陷模链中任意数目耦合模的行为。FDTD模拟和上述实验结果证实了该理论推导结果的定量精确性。少