源-负载耦合发夹梳双频带通滤波器的设计

为得到具有高选择性、小尺寸、低成本的双频带通滤波器,提出了一种具有准椭圆函数响应的双频带通滤波器设计方法.该滤波器利用两组工作于不同工作频率的发夹梳型谐振器,因此能够提供足够的自由度去设计两个独立可控的通带.谐振单元之间的混合电磁耦合可以产生可控的传输零点,而源-负载耦合同样能够在通带外产生传输零点,因此混合电磁耦合与源-负载耦合的结合使阻带内具有多个传输零点,可以有效地提高滤波器的选择性和抑制阻带.最后设计加工了一个工作在2.4和5.2 GHz的双频带通滤波器,测量结果与仿真结果吻合良好,验证了该设计方法的有效性.

Design of Hairpin-Comb Dual-Band Bandpass Filter with Source-Load Coupling

In order to develop dual-band bandpass filters with high selectivity,small size and low cost,a novel method to design the filter with quasi-elliptic response is presented.In this method,two sets of hairpin-comb resonators working at different frequencies are utilized,which provides enough freedom for the independent control of two passbands.The mixed electromagnetic coupling of hiarpin-comb resonators can generate a controllable out-of-band transmission zero,and the source-load coupling can also introduce additional transsmission zeros in the stopband.Therefore,the selectivity and the stopband-restricting ability of the filter are both improved by the transmi-ssion zeros caused as much as possible by the combination of these two couplings.A dual-band bandpass filter ope-rating at 2.4 and 5.2 GHz is finally designed and fabricated,and the measured results accord well with the simulated ones,which means that the proposed design method is effective.