基于新型四模谐振器的双通带带通滤波器设计

Design of dual-band bandpass filter based on novel quad-mode resonator

提出了一种新型的基于双枝节加载的T型四模谐振器,并且利用该谐振器设计了一款双模双通带带通滤波器。首先利用奇偶模分析法以及场分布分析法对四模谐振器的频率特性进行分析,谐振器的每一个谐振模式均可以被独立调节。然后对馈线枝节的参数进行了详细的分析,得到馈线对滤波器外部耦合系数的影响,以调整滤波器通带的带通宽度。接着分析滤波器传输零点产生的原因,得到零点变化的规律,从而调整零点位置,提高滤波器的选择性。缺陷地结构(DGS)被蚀刻在滤波器的金属层底面,以引入非谐振节点,提供源与负载的耦合,可以产生额外的传输零点,进一步提高滤波器的选择性,而且不会增大滤波器的体积。对该滤波器进行加工和测试,仿真结果与测试结果基本吻合。

In this paper,a novel dual-mode dual-band bandpass filter using a quad-mode dual-stub loaded T-type resonator is proposed.The quad-mode resonator is analyzed using odd-/even-mode method.Field distribution of each mode is illustrated,and each mode can be independently controlled.The required extra quality factor (Qe) can be realized by determining the proper feed-lines parameters,and detail analysis is provided to adjust bandwidth of filter passbands.Then the cause of the zero point of the filter transmission is analyzed get the rule of the zero point change is got for adjusting the zero position and improving the selectivity of the filter.defected ground structure (DGS),etched on the bottom metal surface of the filter,working as a non-resonant node (NRN) and proving source-to-load coupling,are utilized to introduce extra transmission zero to improve the passband selectivity without increasing filter volume.The filter was designed and fabricated,and the simulated results are in accordance with the measured results.