矩形槽同轴布拉格结构的模式匹配分析方法及实验验证

Mode-matching analytic method of a coaxial Bragg structure corrugated with rectangular ripples and its experimental verification

基于模式匹配法建立了矩形槽同轴布拉格结构的全波耦合分析模型,推导出了不同模式反射率和传输率的计算式,并采用公开报道的实验数据验证了该理论模型.在此基础上就本文理论与其他相关的理论方法进行了比较,发现以前的理论近似模型由于忽略了矩形槽中的消失模而使传输率的频率响应曲线发生偏差.本文建立的理论方法有望为矩形槽同轴布拉格结构的特性研究和工程实践提供一种理论分析手段.

Based on the mode-matching method, an analytical model with full-wave coupling is presented for the coaxial Bragg structures corrugated with rectangular ripples, where the expressions of the reflectivity and transmission rate for each involved mode are derived. The validity of the analytical model is examined in terms of a reported experiment, and good agreement between the theoretical results and the experimental measurements is demonstrated. Comparative study is carried out between the present model and the published theoretical results. It is found that the approximate treatment adopted by the previous model leads to notable deviation of the transmission response curve due to the neglect of the evanescent modes excited by rectangular ripples. The analytical method presented in this paper can be expected to provide a useful approach to the characteristic investigation and engineering practice of the coaxial Bragg structures with rectangular ripples.