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.
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