多传输零点的新型五通带多模滤波器

New quint-band multimode filter with multiple transmission zeros

针对目前多模滤波器通带数量以及通带选择性有待提高的问题,提出一款新型的基于枝节加载谐振器的五通带多模滤波器。该滤波器采用了一种新型的馈电和耦合方式,可以独立控制外部品质因数和控制多数通带的耦合系数。该滤波器不需要过孔,制作简单。由于源-负载之间的耦合以及多径传输效应的影响,产生了多个传输零点,提高了通带的选择性。进行了滤波器的设计,制作和测试,测试结果与仿真结果吻合,滤波器的五个中心频率位于1.6,3,3.8,4.7,5.7 GHz,其相对带宽分别为12.5%,11.7%,5.48%,8.51%,4.37%。

In order to increase the number of channels and improve passbands selectivity of multi-mode filter, a new quint-band multimode filter based on.stub-loaded resonators was presented. A new type of feeding and coupling structure was employed in this filter, which could individually control external quality factors and couplings of several passbands. The filter possessed the merits of no via holes and easy fabrication. Because of the introduction of source-load coupling and multi-path transmission effect, multiple transmission zeros could be generated, and the selectivity was raised. The filter was designed, fabricated and measured, and the experimental results fit the simulated results well. The center frequencies of the filter are located at 1.6, 3, 3.8, 4.7 and 5.7 GHz, with the relative bandwidths of 12.5%, 11.7%, 5.48%, 8.51% and 4.37%.