结构紧凑的高选择性宽带滤波器

摘 要：为实现结构紧凑和高选择性的宽带滤波器，在传统平行耦合线结构的基础上，作了适当改进，设计了三种结构新颖的三线耦合结构，均能够实现具有三个传输零点的宽带响应，且其中两个零点分别紧靠通带的上下边缘。加工并测试了基于其中一种结构的宽带滤波器，工作频率为2.6GHz，3dB相对带宽为63%，三个传输零点分别位于1.46GHz，3.77GHz和5.13GHz，介质基板采用Rogers 4003，厚度0.813mm。实测结果与仿真结果吻合良好,验证了结构的有效性。

Compact wideband bandpass filters with high selectivity

To achieve compact and highly selective wideband filter, on the basis of the traditional parallel coupled line structure, we make the appropriate improvements.Three novel three coupled line structures are designed in this letter. All structures exhibit a wideband response with three transmission zeros and two of them are close to the upper and lower edges of the passband. One filter has been designed, fabricated and measured. The operating frequency of filter is 2.6GHz, 3-dB fractional bandwidth (FBW) of the filter is 63%, transmission zeros are located at 1.46GHz, 3.77 GHz and 5.13 GHz respectively. The filter is designed on a Rogers 4003 dielectric substrate and the thickness of filter is 0.813mm.Good agreement between the measured results and simulation ones are obtained,verifying the validity of structures.