【作者】 吴琼；

【导师】 高隽； 蔡德林；

【作者基本信息】 合肥工业大学 ， 计算机应用， 2005， 硕士

【摘要】 电磁带隙(Electromagnetic Band Gap,EBG)结构为一个折射率周期变化的三维物体,周期为入射波长量级,它的应用前景极为广泛,在微波领域,特别是微波电路和天线领域中有着巨大的应用价值,将是新一代微波器件的基础。因此近年来,EBG结构越来越引起人们的关注。然而电磁带隙的设计较普通微波器件的设计难度大,设计成本高,这就给实际工程设计带来了现实问题:如何在保证精度的前提下缩短设计周期,降低研制成本。 对此,本文主要研究了电磁带隙的优化设计,其中数值计算部分采用时域有限差分方法、优化部分采用人工神经网络模型结合遗传算法来完成。论文首先介绍了时域有限差分方法、人工神经网络模型和遗传算法的基本原理,开发了相应的计算程序。在讨论了各种方法之后都用相应的实例来说明该方法解决问题的有效性,同时验证了所开发程序的正确性;然后针对具体的电磁带隙结构,将上述三种方法结合起来用于解决电磁带隙的实际工程问题,详细论述了从人工神经网络的建模到遗传算法的优化,最后得到经过优化的结构参数。为了验证该方法处理这类问题的有效性,文中用商业软件仿真经过优化得到的电磁带隙结构,并将结果进行比较,二者吻合良好,从而表明该设计方法取得了较好的效果。 本文的工作,为电磁带隙的工程优化设计提供了一种有效途径,在实现缩短设计周期,降低研制成本方面作了有价值的实践。更多还原

【Abstract】 Electromagnetic band gaps are periodic dielectric and metallic structures in which the refractive index modulation gives rise to stop bands for electromagnetic (EM) waves within a certain frequency range in all directions. In recent years, electromagnetic band gap (EBG) materials have attracted much attention, and many possible applications of such materials were proposed and demonstrated. Research on electromagnetic band gaps, and devices based on them, is exciting and fast-moving. Practical devices are likely to emerge during the next few years. So, electromagnetic band gap received more and more attentions, but it has more difficulty than common microwave devices in engineering design. This inevitably create a problem: how to ensure the precision and reduce the design cost.Basic principles of finite-difference time-domain method, artificial neural network model and genetic algorithm were introduced in this paper, and computer programs were developed. Three methods have been combined to solve the engineering problem of electromagnetic band gap. This approach was validated by the results obtained by commercial package, Ansoft HFSS.Effective approach of engineering optimum design of electromagnetic band gap, and useful practices of reducing the design cost were provided.更多还原