平行耦合微带线输出带通滤波器的最优化设计

Designing an Optimum of Parallel Coupled Miorostrip Line Output Bandpass Filter

本文在相关数学模型的基础上，推导出平行耦合微带线和平行耦合微带线输出带通滤波器插损的精确表达式。并以带通滤波器插损作为目标函数，以降低损耗为目的，进行带通滤波器的最优化设计。具体实例的设计表明，在不改变原设计性能指标的基础上，经过优化处理之后的带通滤波器各平行耦合对之间的缝隙ｓ／Ｈ明显减小，导致总的插损大大减小，从而改善了带通滤波器的滤波性能。

The precise expression for the insertion loss of the parallel coupled microstrip line output bandpass filter has been given on the basis of related mathematical models. We have carried out the optimization design of the bandpass filter for the sake of minimum insertion loss with the total insertion loss being the object function. In the meantime, the corresponding FORTRAN 77 program has been running successfully. A concrete designing example shows that on the basis of optimization design, the gaps s/H of almost all the parallel coupled microstrip lines in the output bandpass filter become obviously narrow and this results in the decrease of the total insertion loss and therefore the bandpass filter performance is improved.