新型超宽带复合左右手传输线的设计与实现

Design and realization of novel ultra wide band CRLH transmission line

提出了一种基于共面波导的新型超宽带复合左右手传输线(CRLH TL)。根据Bloch周期电路理论,由单元集总等效电路模型,推导出左、右手频率范围和相应的相速、衰减特性,提取了传输线的等效本构参数。新结构左、右手参数独立可控,设计、调整方便;相比常见的交指或缝隙耦合,面面耦合形成的串联电容可以有效抑制高频谐振,拓宽传输线通带。实验结果表明:新型传输线具有较小的损耗和超宽通带,适用于超宽带微波器件。

A novel ultra wide band composite-right/left handed （CRLH） transmission line （TL） based on the coplanar waveguide （CPW） structure is proposed. Based on Bloch theory, the analysis of the pass-band of LH/RH, the velocity of phase, attenuation and impedance characteristics of the proposed structure is derived from the lumped element equivalent circuit model of the unit cell. Moreover, the effective medium parameters are extracted. Since the right/left-handed parameters of the proposed structure can be controlled separately, the design and tune are more flexible. Compared with the inter-digital and gap coupled structures, the surface-to-surface coupled structure can avoid the resonance at high frequency, which results in broader pass-band. It can be observed from the measured results that the fabricated CRLH TL shows low insertion loss and ultra wide pass-band for ultra wide band applications.