基于分形几何与复合左右手传输线的混合技术方法，提出了一种新型小型化微带双工器并对其进行了研究。该双工器将工作于一对不同频率的两个三端口网络进行合成，由构成其左手部分的集总元件和右手部分的Sierpinski分形微带线组成。双工器的小型化得益于Sierpinski分形曲线的空间填充特性。而双工器的双频特性是由于复合左右手传输线具有双曲色散关系。为验证所提方法的有效性，成功设计了基于不同Sierpinski迭代次数的双工器。为证实仿真结果，加工测试了基于Sierpinski二次迭代分形的复合左右手双工器。仿真结果与测试结构吻合的很好。与未采用分形结构的传统复合左右手双工器相比，所制作的双工器工作于GSM两个频段(0.9和1.8 GHz)并获得了良好的通带性能和小型化比例，最大小型化比例达76.3%。

A new type of miniaturized microstrip diplexer is initially proposed based on the combined technology of fractal geometry and composite right/left handed transmission line (CRLH TL). The diplexer which is synthesized by combining two 3-port networks operating at a pair of different frequencies consists of lumped elements for the left handed (LH) part and Sierpinski-shaped microstrip lines (MLs) for the right handed (RH) part. Sierpinski curve allows miniaturized dimensions of the diplexer mainly attributing to its strong space-filling capability. CRLH TL enables dual-band design due to its unique hyperbolic-linear dispersion relation. For demonstration, three CRLH diplexers using Siepinski curves of different iteration orders are successfully designed. For verification, a CRLH diplexer sample by adopting a Sierpinski curve of second order was fabricated and measured. Consistent numerical and experimental results have confirmed the design. The fabricated diplexer operating at 0.9 and 1.8 GHz, respectively achieves good in-band performances and a maximal 76.3% size reduction compared to the conventional CRLH diplexer without fractal geometry.