基于分支线加载的紧凑微带双通带滤波器设计

提出了一种紧凑的零度馈电的具有分支线加载的具有3个传输零点的微带双带通滤波器。首先完成了中心频率2．4 GHz的微带单带通滤波器设计，再次完成了加载分支线的优化仿真设计，最终实现了2．4／3．5 GHz微带双通带滤波器，实测和仿真结果吻合较好，实测得到了的第一、二通带相对带宽大于5％，第一通带内插损小于1．5dB，第二通带内插损小于3 dB。提出的分支加载的微带双带通滤波器具有设计简单、结构紧凑、很好的选择性等优点，可以满足无线局域网（WLAN）系统和固定无线接入（FWA）通信需要。

Design of Compact Microstrip Double Passband Filter Based on Stub- Loaded Resonators

A compact microstrip dual -band passband filter with three transmission zeros using open stub loaded resonator and 0 - degree feed structure was presented. First, the design of the 2.4 GHz pass-band filter was completed. Second, the optimization simulation loading the branch line is completed too.Finnally, the 2.4/3.5 GHz dual - band microstrip passband filter was fabricated. The measured results ofthe filter was in good agreement with the simulation. The fractional frequency bandwidths of the measureddual passbands are greater than 5 %. The insertion loss of the low - band is below 1.5 dB. The insertionloss of the high - band is below 3 dB. So the proposed dual - band microstrip passband filter based onStub- Loaded Resonators not only has high selectivity, but also is compact in size, and easy to designand realize. It can meet the 2.4 GHz and 3.5 GHz wireless communication requirements such as short -range wireless communication in WLAN and FWA application.