一种SIR结构的超宽带带通滤波器

An Ultra-wideband Bandpass Filter Based on SIR Structure

提出了一种基于阶梯阻抗谐振器(Step Impedance Resonator,SIR)结构的具有平行耦合微带线的超宽带(Ultra-wideband,UWB)带通滤波器。滤波器采用孔径补偿技术设计,在地面上蚀刻两个矩形槽,以增强顶层微带线之间的耦合。为了优化S参数并改善带外的抑制,在谐振器中采用了缺陷微带结构(Defective Microstrip Structure,DMS)。仿真结果表明,滤波器的通带范围为2.3～6.1 GHz,中心频率为4.2 GHz,分数带宽(Fractional Bandwidth,FBW)大于90.4%;插入和回波损耗分别优于-1 dB和-10 dB;通带中群延迟的变化范围为0.4～0.6 ns,滤波器的线性度良好。该滤波器可用于5G通信系统。

An ultra-wideband(UWB)bandpass filter with parallel coupled microstrip lines based on step impedance resonator(SIR)structure is propsed.The filter is designed using aperture compensation technique which etches two rectangular slots on the ground to enhance the coupling between the microstrip lines on the top layer.In order to optimize the S parameter and improve the suppression out of the intersting band,the defective microstrip structure(DMS)is adopted in the resonator.The results of simulation show that the passband range of the filter is 2.3~6.1 GHz,the center frequency is 4.2 GHz and the fractional bandwidth(FBW)is greater than 90.4%.The insertion loss and return loss are better than-1 dB and-10 dB,respectivety.The variation range of group delay in passband is 0.4~0.6 ns and the linearity of filter is good.The filter can be applied in 5G communication systems.