基于缺陷地结构的微带低通滤波器设计

提出了一种具有宽带带外抑制的小型化微带低通滤波器。该滤波器由缺陷地结构和两阶阶跃阻抗单元结构构成。利用ANSYS HFSS建立三维全波电磁模型并仿真优化，仿真结果表明:该低通滤波器的截止频率为1.4 GHz，通带宽度为0~1.4 GHz，通带内的插入损耗小于0.5 dB，带外抑制频率范围为2.1~11 GHz，在阻带范围内的带外抑制能力接近20 dB。为验证仿真和测试结果，加工并测试了经全波电磁优化后的缺陷地结构微带低通滤波器。测试结果和仿真结果吻合得较好，证明了所提出的缺陷地结构在实现滤波器小型化和宽阻抗带宽上有着重要的作用，能够使该滤波器具有较好的低通滤波特性。

Design of defected ground structure microstrip low-pass filters

A novel compact microstrip low-pass filter with wideband suppression is proposed in this paper. The filter is composed of defect ground structure (DGS) and stepped impedance structure unit. The model was built and optimized by ANSYS HFSS. The simulation results show that the cut-off frequency of the low-pass filter is 1.4 GHz, the passband width is 0-1.4 GHz, the insertion loss in the passband is less than 0.5 dB, the out-of-band rejection frequency width is from 2.1 GHz to 11 GHz, and the out-of-band rejection in the stopband range is about 20 dB. In order to verify the test results and simulation results, an optimized defect-structured microstrip low-pass filter was processed and tested. The practical measurement are in good agreement with the simulation results. It is proved that the defect ground structure plays an important role in realizing the miniaturization of the filter and the wide impedance bandwidth. Moreover, the defect ground structure provides better low-pass filtering characteristics to the filter.