基于新型对偶复合左右手传输线的高性能带阻滤波器设计

 利用交指螺旋线结构和枝节贴片设计了一种新型对偶复合左右手传输线结构.采用电磁全波仿真软件和Bloch-Floquet 理论对其进行研究，计算并提取了其色散曲线，研究结果表明该对偶复合左右手传输线结构具有良好的带阻特性，并且阻带内2个传输零点独立可控．在此基础上采用2个单元结构级联的方式设计了一款具有小型化特性的性能优越的带阻滤波器，进行实物加工并使用适量网络分析仪测试，测量结果与仿真结果吻合较好，表明所设计的带阻滤波器中心频率为3.56 GHz，阻带带宽为39.3%，阻带矩形度为0.85，通带带宽为4.47~8.42 GHz，整体性能优越．此外所设计的带阻滤波器整体尺寸为0.237λ×0.145λ（λ为中心频率在自由空间波长），小型化优势明显．

Design of bandstop filter with good performance based on novel dual composite right/left handed transmission line

A novel dual composite right/left handed transmission line （D-CRLH TL） was designed by using structure of spiral inter-digital figures and stub with rectangular patch. Its structure was analyzed by full wave electromagnetic simulator and Bloch-Floquet theory， the dispersion curve was calculated. The simulated results showed that the designed D-CRLH TL had good bandstop performance and the two transmission zeros could be controlled independently by adjusting the physical parameters. Then， based on this novel D-CRLH TL， a miniaturized bandstop filter with good performances was designed， fabricated and measured with good agreement to the simulated results， showing that this designed filter centered at 3.56 GHz， the stop bandwidth was 39.3%， the shape factor was 0.85， the passband out of the stopband in high frequency was 4.47-8.42 GHz， and the whole electromagnetic performances are perfect. Moreover， the size of this designed filter was 0.237λ×0.145λ （λ was the wavelength of center frequency in the free space）， and the miniaturization was realized．