基于DGS结构的抑制谐波低通滤波器设计

Design and Realization of Harmonic-Suppressed Low-Pass Filter Using Defected Ground Structure

运用DGS等效电路模型与HFSS三维全波仿真相拟合的方法提取出DGS的结构参数,并将该结构应用于交指椭圆函数低通滤波器中,提出了一种新型的DGS滤波器.将交指滤波器两侧馈线设计成阻抗补偿馈线结构,将确定了结构参数的DGS蚀刻于补偿线下方的接地层上,再通过HFSS三维仿真进行匹配优化,得到了通带平坦、阻带宽、结构紧凑的DGS滤波器.实际制作的滤波器测试与仿真结果基本吻合,对谐波具有良好的抑制作用.

This paper presents a method to use the equivalent-circuit model and 3-D model simulation for the DGS to extract the dimension parameters. Combining an inter-digital elliptic-function low-pass filter with the DGS structure, a novel filter is proposed. A compensated feed-line structure on the side of the inter-digital elliptic- function low-pass filter is designed, and a couple of suitable DGSs are etched under compensated lines. Furthermore, full-wave simulation and optimization of the proposed filter are obtained with HFSS to get better impedance match. The design gives performances of a fiat passband, a wide stopband and a compact structure. Agreement between experimental results and measurements shows validity of the DGS filter, which has good harmonic-suppressed characterizes.