改进的电磁混合耦合SIW超宽阻带滤波器设计

Design of a Modified Electromagnetic Hybrid Coupling SIW Ultra-Wide Stopband Filter

为了提升滤波器的阻带性能,提出了一种改进的电磁混合耦合基片集成波导(Substrate Integrated Waveguide,SIW)超宽阻带滤波器的设计。首先,利用模式的本征抑制和电磁混合耦合方法,合理地设置外部馈电端口、内部耦合窗口及内部耦合圆孔阵列,抑制了频率低于TE105和TE501的所有高次模;其次,利用耦合槽的偏移,在中间金属层侧壁中心约为1/10腔体宽度处刻蚀耦合槽,可同时抑制TE105和TE501以及TE305和TE503模的耦合;最后,仿真结果显示,该滤波器的中心频率f0=5.94GHz,相对带宽为3.37%,插入损耗为2.29 dB,回波损耗优于17.1 dB。当阻带宽度延伸至4.85f0时,抑制深度优于20 dB。综上,探讨了基片集成波导超宽阻带滤波器的宽阻带抑制,有效延伸了阻带宽度,为移动通信系统进一步提升抗干扰性能奠定了技术基础。

In order to improve the stopband performance of the filter,a modified design of electromagnetic hybrid coupling SIW(Substrate Integrated Waveguide)ultra-wide stopband filter is proposed.First,the external feed ports,the internal coupling windows and the internal coupling circular hole arrays are set reasonably by using the mode intrinsic suppression and electromagnetic hybrid coupling method,and all the higher modes with frequencies lower than TE105 and TE501 are suppressed.Then,the coupling modes of TE105 and TE501 as well as TE305 and TE503 can be suppressed simultaneously by etching the coupling groove at the center of the side wall of the intermediate metal layer about 1/10 cavity width by using the offset of the coupling groove.Finally,the simulation results indicate that the center frequency of the filter is f0=5.94 GHz,the relative bandwidth is 3.37%,the insertion loss is 2.29 dB,and the return loss is better than 17.1dB.When the stopband width is extended to 4.85 f0,the suppression depth is better than 20 dB.In summary,this paper explores the wide stopband suppression of substrate integrated waveguide bandpass filters and effectively extends the stopband width,laying a technical foundation for further improving the anti-interference performance of mobile communication systems.