频变耦合双通带滤波器的综合方法

为了解决频变耦合双通带滤波器缺少有效综合方法的问题,文中提出一种优化综合方法。该方法首先通过频率变换技术得到滤波器在归一化双通带域内的特征多项式,然后应用经典的耦合矩阵综合方法得到双通带滤波器的全规范耦合矩阵,进而以矩阵的特征值为趋近目标构造目标函数,最后应用梯度优化算法进行优化获得了双通带滤波器的频变耦合矩阵。文中对对称型和非对称型频变耦合双通带滤波器进行了验证。验证结果显示,两种类型滤波器的双通带都能够较好地保持等波纹特性,证明了综合方法的有效性。

A Synthesis Method for Dual-Band Filters with Frequency Variant Couplings

In order to solve the problem of the lack of effective synthesis method for frequency-varying coupled dual-band filter, an optimized synthesis method is proposed in this study. First, the characteristic polynomials of the filter in the normalized dual pass band domain are obtained using the frequency transformation technique. Then, the classical coupling matrix synthesis method is used to obtain the canonical coupling matrix of the dual band filter and the cost function is constructed with the eigenvalues of the matrix as the approach target. Finally, the coupling matrix can be obtained by gradient optimization algorithm. The symmetrical and asymmetrical frequency-variable coupled dual band filters are verified. The verification results show that the dual-band of the two types of filters can better maintain the iso-ripple characteristics, which proves the effectiveness of the integrated method.