基于混合左右手和人工传输线的平面双定向耦合器

Bi-directional coupler based on composite right/left-handed and artificial transmission lines

摘要: 利用人工传输线作为右手传输线，与混合左右手传输线(CRLH-TL)进行耦合，实现左手传输线和右手传输线的混合耦合，构造了一种新型的定向耦合器。该耦合器具有后向耦合、小型化、结构紧凑的特点。实验测试结果表明：耦合器的工作频率在1.3~1.8 GHz，相对百分比带宽达到32%，实现了10 dB的耦合度，比常规微带线定向耦合器具有更大的耦合度调节范围,隔离度大于25 dB。实验测试结果与电磁仿真结果相吻合。

Abstract: An artificial transmission line as a right-handed transmission line is edge-coupled with a CRLH-TL to realize coupling between the left-handed and the right-handed transmission line. The directional coupler is a compact planar structure with characteristics of backward and tight coupling. Experimental results show that a 10 dB coupling coefficient is achieved from 1.3 GHz to 1.8 GHz. The corresponding fractional bandwidth is about 32%, and the isolation is greater than 25 dB. Simulation results agree well with measured results. The directional coupler covers a wider coefficient range than the conventional one.