带状线交指滤波器电容间隙的准确设计

Accuracy Design of Capacitive Gap for Strip Line Interdigital Filters

在L、S等较低的微波频段,带状线交指滤波器是常用的滤波器之一,一般情况下文献上只给出比较详细的矩形杆间距和带状线宽度的设计公式,对于谐振杆长度l或者端间隙Sa的确定,以及终端杆边距So的确定,仍然要通过实验方法不断修改多次才能完成。本文在工程实践与分析研究的基础上,提出了十分简单准确有效的电容间隙Sa的设计方法,即Sa=b/4,不再需要繁琐的近似计算以及大量的实验过程和高频仿真,解决了一直困扰工程师的一个难题。

In lower microwave bands such as L and S band, the stripline interdigital filter is one of frequently used filters. Generally, the formula for designing rectangular bar space and stripline width is presented in detail in the reference, but for determining length i of the resonance bar or the gap between terminals as well as margin So of the terminal bar, it can not be completed until it is modified for many times by using experimental method. This paper presents a method of designing capacitive gap Sa, i. e Sa=b/4, it is simple, accurate and effective. The numerous approximation calculation and a great deal of experimental procedures and high frequency simulation are no longer needed, so a problem puzzling the engineer is solved.