基于DGS结构的微带岔线型带通滤波器设计

Design of Microstrip Bandpass Filter Using Defected Ground Structure and Spurline

本文介绍了一种基于缺陷地结构(DGS)的微带岔线型宽带带通滤波器的设计过程。此滤波器以四分之一波长的开路枝节型带通滤波器为原型进行设计和改进,引入了微带岔线和DGS结构,在增加通带带宽和阻带带宽的同时,使滤波器的带外谐波抑制和带内回波损耗得到了很大的改善。采用HFSS三维场仿真软件进行S参数的仿真,从仿真结果可以看出,所设计的带通滤波器中心频率为11.5GHz,其3dB相对带宽大于50%,带内插损小于0.3dB。此外,在1-6GHz的第一阻带内,滤波器的带外抑制大于20dB,最大抑制度为52dB;在15-24GHz的第二阻带内滤波器的带外抑制大于20dB,最大抑制度为46dB。整个滤波器尺寸仅为12mm×16mm。

A wideband microstrip bandpass filter(BPF)using DGS and spurline is presented.Design of the filter is based on the λ/4 open stub bandpass filter.With using the spurline and DGS,both the bandwidth of passband and stopband are improved,besides,the harmonic suppression and return loss are greatly improved.The advanced electromagnetic microwave simulation software HFSS is used to get S-parameters.The simulation result shows that the filter has a wide 3dB fractional bandwidth which is more than 50% at the center frequency of 11.5GHz.From 1-6GHz in the first stopband,the proposed BPF has a rejection of better than 20dB and the maximum rejection level of 52dB.From 15-24GHz in the first stopband,the proposed BPF has a rejection of better than 20dB and the maximum rejection level of 46 dB.The proposed BPF has a compact structure of 12mm×16mm.