中文摘要：

针对传统双频耦合器工作带宽窄的问题,提出了一种基于阶梯阻抗谐振器（SIR）的双频宽带分支耦合器设计方法.通过调节SIR的阻抗,可以在工作的双频段（高低频段）上灵活地调节耦合器谐振频率的位置和耦合器的带宽.最后设计并加工了一个工作在2.20和5.50GHz的双频宽带3 dB分支耦合器.该耦合器覆盖了全球移动通讯系统的1.80GHz频段和无线局域网系统的2.45、5.25、5.80 GHz频段.测量结果与仿真结果吻合良好,验证了文中双频宽带耦合器设计方法的有效性.

英文摘要：

As the conventional dual-band coupler is of narrow operation band,this paper presents a novel design method of dual-band broadband branch-line coupler based on stepped impedance resonator（SIR）.With this method,both the location of resonate frequencies and the bandwidth of the coupler can be adjusted in the lower and upper frequency bands.A dual-band broadband 3-dB coupler operating at 2.20/5.50GHz is also designed and fabricated,which covers not only the 1.80GHz GSM band and but also the 2.45/5.25/5.80GHz WLAN bands.The measured results accord well with the simulated ones,meaning that the proposed design method is feasible.