混合型开槽同轴布喇格结构的比较研究

Comparative study of coaxial Bragg structure with hybrid ripples shape

基于电磁仿真软件(Computer Simulation Technology,CST)平台,对几种不同开槽形状同轴布喇格结构的频率响应特性分别进行了数值模拟比较研究.结果表明:三角形开槽带宽最窄而矩形开槽带宽最宽;交替混合型开槽时耦合模式的反射率明显提高,而分半混合型开槽时不仅耦合模式的反射率提高,且其带宽也明显变宽,但两种开槽方式时工作模式的反射率和带宽都位于单一开矩形槽和三角形槽之间;叠加混合型开槽克服了单一矩形槽和三角形槽存在奇点和边界突变的缺点,对模式的选择性能优于矩形开槽,反射率和带宽又大于正弦开槽和三角形开槽,仅其谐振频率点有偏移.这些特点有利于同轴布喇格结构的模式选择、散热和工业生产.

Based on the Computer Simulation Technology (CST) software, numerical simulations are carried out for comparative study about the frequency response characteristic of the coaxial Bragg structure with different ripples shapes. Results show that the triangular ripples has the narrowest bandwidth, while the bandwidth of rectangular ripples is the widest. Moreover, the reflectivit of coupling mode is obviously improved with the alternate hybrid ripples, and for the half-and-half ripples, the reflectivity of coupling mode is improved and its bandwidth is widened. Besides, whether coaxial Bragg structure employs the alternate hybrid ripples or the half-and-half ripples, the reflectivity and the bandwidth of the working mode are both between the sole rectangular ripples and triangular ripples. However, the overlie ripples overcomes the defects that the sole rectangular ripples and triangular ripples have singularity and sudden border changes, and its mode selectivity is better than rectangular ripples, furthermore its reflectivity and bandwidth are better and wider than that of the sole sinusoidal and triangular ripples, excepting the minus deviation of its syntony frequency point. These features are propitious to the mode selectivity, heat dissipation and the machining manufacture of the coaxial Bragg structure. Copyright © 2015 by Editorial Department of Chinese Journal of Radio Science