基于参数提取和空间映射的滤波器优化设计

Optimization Design of Filters Based on Parameter Extraction and Space Mapping

为提高微波带通滤波器的设计效率,提出了一种基于参数提取和空间映射的滤波器优化设计方法.即采用柯西-最小二乘法获得滤波器的有理分式模型,针对该模型给出了一种快速收敛的目标函数,提取出滤波器的等效电路参数;根据空间映射的思想,把滤波器最佳尺寸的求解问题转换成一个有二次约束的优化模型,利用求解结果指导滤波器的全波仿真.最后设计并加工了一款双模圆波导滤波器,经过6次迭代即可得到理想响应对应的最佳尺寸,测试结果和仿真结果吻合良好.

In order to improve the design efficiency of microwave bandpass filters,an optimization design method is proposed based on the parameter extraction and the space mapping.In this method,first,the Cauchy-TLS（Total Least Squares） method is used to obtain the rational fraction models of the filters.Next,by using these models,a fast convergent objective function is constructed to extract the equivalent circuit parameters.Then,according to the principle of the space mapping,the problem of solving the optimal physical dimension of the filter is transformed into a quadratic constrained optimization model,and the corresponding solution is used to guide full-wave simulation of the filters.Finally,a dual-mode circular-waveguide filter is designed and machined,and its optimal physical dimension with ideal response is achieved after six iterations.It is found that the measured results accord well with the simulated ones.