基于新型D-CRLH-TL的双频带阻滤波器设计

Design of Dual-Band Bandstop Filter Based on Novel D-CRLH-TL

通过将对称交指螺旋线应用于传统的对偶复合左右手传输线(D-CRLH-TL)结构,改进设计了一种新型的D-CRLH-TL结构。采用全波仿真软件对其电磁特性进行了研究,结果表明:改进结构具有良好的带阻特性,阻带内具有两个相互独立的传输零点,并且整体尺寸减小了30%,有效地实现了小型化。在此基础上,利用所提出的D-CRLH-TL结构设计了一款性能优越的双频带阻滤波器。对所设计滤波器进行实物加工并测试,结果表明所设计的滤波器两个阻带中心频率分别为3.47GHz和5.21GHz,阻带带宽分别为26.8%和10%,能够有效抑制WLAN和WMAX频段对超宽带通信的干扰。同时,相比于传统的带阻滤波器结构,所设计带阻滤波器的整体尺寸为20.9mm×12.6mm(0.24λ×0.15λ),仅为传统结构的50%,小型化优势明显。

A novel dual composite fight/left-handed transmission line （D-CRLH-TL） is revised designed in this paper by applying the symmetrical spiral-inter-digital figures to the traditional structure of D-CRLH-TL. Its electromagnetic charac- teristics are analyzed by the full wave simulator, and the simulated results show that this novel D-CRLH-TL has a good stop- band with two controlled transmission zeros, compared with the traditional structure, it realizes a 30% size reduction. Then, a du^-band bandstop filter with good performance is designed, fabricated and measured based on this novel D-CRLH-TL, the measured results show that the two stopband centered at 3.47GHz and 5.21GHz, and the bandwidth is 26.8% and 10% re- spectively, this filter can avoid the interferences come from the signals of WLAN and WMAX effectively. Moreover, com- pared with the traditional bandstop filter, the whole size of this designed bandstop filter is 20.9mm×12.6mm（0.24λ×0.15λ）, and a 50% size reduction is realized.