具有良好选择性及带外抑制的小型低通滤波器  

Compact Lowpass Filter with Sharp Rejection and Wideband Suppression

作　　者：宋翔宇[1] 李恩[1] 

机构地区：[1]电子科技大学电子工程学院,成都611731

出　　处：《微波学报》2010年第S1期333-335,共3页Journal of Microwaves

摘　　要：本文提出了一种具有良好选择性以及宽带带外抑制的小型低通滤波器结构。滤波器的每一级由一段微带线和交指电容构成。基于对每一级结构的分析,我们可以确定通带的范围。为了进一步提高带外的抑制性,对单级滤波器进行了周期性的级联。通过产生多个带外衰减极点来实现带外的宽带抑制。此滤波器3dB截止频率3.67GHz,带内插损-0.9dB,带内回波损耗低于-13dB。通带到阻带的选择度为160dB/GHz。带外抑制从3.8GHz到13.1GHz低于-20dB。A compact lowpass filter with ultra sharp rejection and wideband suppression is proposed in this paper.Each section is composed of a microstrip line and an inter-digital capacitor.Based on the theoretical analysis of the single section,one could easily achieve the passband limit with good selectivity.To further improve the stopband performance,a periodically cascaded section structure is employed,which leads to multi transmission zeros to suppress the spurious.To verify the mechanism above,a filter is designed and fabricated.The measured result shows good insertion loss less than-0.9 dB over 95% of the passband and return loss is below-13 dB.Measured passband to stopband attenuation slope is 160 dB/GHz.Specifically,the proposed filter possesses a stopband up to 13.1 GHz with a satisfactory rejection greater than-20 dB.

关 键 词：交指电容 良好选择性 宽带带外抑制 小型化 

分 类 号：TN713[电子电信—电路与系统]