一种新型小型化交叉耦合带通滤波器的设计

Design of the Novel Miniaturized Cross-Coupled Band-Pass Filter

本文设计了一种基于阶跃阻抗谐振器的新型嵌入式交叉耦合带通滤波器.为使滤波器小型化,设计了两种紧凑型阶跃阻抗谐振器结构.通过研究和改善谐振器间的耦合机制,可使两种谐振器不仅形成嵌入式结构,而且缩减了馈线占据的面积,进一步减小了含馈线在内整个带通滤波器的尺寸.为验证此方法的可行性,利用滤波器综合法设计了一个中心频率为2.4GHz,相对带宽FBW为15%的4阶交叉耦合带通滤波器,其最终设计尺寸为28mm×20mm(0.37λ_g×0.26λ_g,λ_g为中心频率所对应的导波波长).对该滤波器进行了仿真、加工和测试,结果表明该滤波器具有所需的广义切比雪夫特性,且互相吻合得很好.

A novel embedded cross-coupled filter based on stepped impedance resonators is proposed in this paper.Two kinds of compact stepped impedance resonator structures are designed to realize the miniaturization of the filter.By studying and improving the coupling mechanism,the two resonators can not only form the embedded structure,but also reduce the area occupied by the feed line,which further reduce the size of the whole band-pass filter including the feed structure.In order to verify the feasibility of this approach,fourth-order cross-coupled band-pass filter with center frequency of 2.4GHz and relative bandwidth of 15% was designed by using filter synthesis method..The filter occupies a very small size of 28mm×20mm（0.37λ_g×0.26λ_g,where λ_g is the guided wavelength corresponding with the center frequency）.Finally it is fabricated and measured.The measured and simulated results show that the filter has the generalized Chebyshev characteristics,and they match each other very well.