基于耦合线加载开路枝节的宽带带阻滤波器设计

Design of wideband bandstop filter based on coupled lines loaded open-circuited stubs

基于单端接地耦合线结合微带传输线加载开路枝节,提出了一款宽带带阻滤波器。该滤波器由输入输出端的单端接地耦合线并联微带传输线上加载三个开路枝节组成。采用奇偶模理论分析、传输线模型和结构模型仿真优化,对滤波器的特性开展了研究。实物加工测试结果与仿真结果的一致性好,验证了所设计的宽带带阻滤波器。该滤波器的阻带中心频率为2 GHz,3 dB衰减带宽为98%(1.19~3.15 GHz),20 dB衰减带宽为84.5%(1.24~2.93 GHz),阻带带内抑制大于35 dB,结构紧凑,可与航电系统设备板级电路集成,用于电磁干扰防护。

A wideband bandstop filter was proposed based on coupled lines with single-ended ground and microstrip transmission lines combined with open-circuited stubs.The filter consists of coupled lines with single-ended ground shunted at input and output ports and microstrip lines loaded with three open-circuited stubs.Characteristics of the filter were analyzed by using even-and odd-mode analysis method,transmission line model and physical structure model.Comparison between simulated and measured results shows good consistence,which validates the the proposed wideband bandstop filter.Central frequency of the stopband is 2 GHz.3 dB attenuation bandwidth of the stopband is 98%(1.19 GHz to 3.15 GHz),while 20 dB attenuation bandwidth is 84.5%(1.24 GHz to 2.93 GHz).Stopband suppression of the filter is greater than 35 dB.Compact structure of the bandstop filter make it suitable for integration with circuits of avionics system and equipment for EMI protection.