基于FASIRs的平衡单端口多传输零点的滤波功分器设计

Balanced-to-Single-Ended Filtering Power Divider with Multiple Transmission Zeros Based on FASIRs

本文设计了一种基于折叠非对称阶跃阻抗谐振器(FASIRs)的双频带平衡-单端(BTSE)滤波功率分配器(FPD)。基于传统的非对称阶跃阻抗谐振器的分析,得到了FASIR的两个谐振频率,它们可以独立控制。同时,利用所提出的FASIRs,设计了一种双频带平衡带通滤波器(BPF),以进一步优化滤波特性。为了获得更好的频率选择性,通过改变馈线的结构和位置,产生了更多的耦合路径,实现了七个传输零点(TZs)。最后,在所提出的BPF的基础上,实现了一种具有原始良好滤波特性和紧凑尺寸的双频带BTSE FPD。为了提高隔离性能,隔离电路是通过在输出端口之间加载一个接地电阻器的搭接线来设计的。同时,创新地采用了魔T方法来分析隔离特性。为了验证设计概念,制作和测量一个双频带BTSE FPD。可以观察到测量结果和仿真结果之间有很好的一致性。

A dual-band balanced-to-single-ended(BTSE)filtering power divider(FPD)is designed using folded asymmetric stepped impedance resonators(FASIRs).Based on the analysis of the traditional asymmetric stepped impedance resonator,two resonant frequencies of FASIR are obtained,which can be quasi-independently controllable.Meanwhile,by employing the presented FASIRs,a dual-band balanced bandpass filter(BPF)is designed to further optimize the filtering characteristics.To gain superior frequency selectivity,more coupling paths are generated by changing the structure and position of the feedlines.Thereby,seven transmission zeros(TZs)are realized.Finally,on the basis of the proposed BPF,a dual-band BTSE FPD with the original good filtering characteristics and compact size is realized.In order to improve the isolation performance,the isolation circuit is designed by employing a stub loaded with a grounded resistor between the output ports.Meanwhile,a magic-T method is innovatively employed to analyze the isolation characteristic.To validate the design concept,a dual-band BTSE FPD have been fabricated and measured,respectively.A good agreement between the measurement and simulation results can be observed.