基于正六边形QMSIW的小型化双通带滤波器设计

Design of miniaturized dual passband filter based on regular hexagon QMSIW

为满足多业务无线通信系统对射频器件高性能、小型化的应用需求,提出了一种基于正六边形四分之一模基片集成波导(QMSIW)加载对称微带开路枝节(MOS)结构的小型化双通带滤波器。利用两个QMSIW谐振腔的基模和一对MOS谐振器的准TEM模可分别形成两个相对独立的通带,测得该双通带滤波器中心频率位于5.39 GHz和10.12 GHz,3 dB带宽分别为11.48%和4.34%。通过模式交叉耦合、缝隙混合耦合在6.78,8.75和11.68 GHz处产生3个传输零点,显著提高了滤波器的选择性和带外抑制度。该滤波器有效尺寸约为0.63λ_(g)×0.34λ_(g),相较于传统设计减小了75%。最终的测试结果和仿真结果基本一致,证明了该设计方法的可行性。

To achieve high performance and miniaturization of RF devices in multi-service wireless communication systems,a dual passband filter was designed based on regular hexagon quarter-mode substrate integrated waveguide(QMSIW)loaded with symmetric microstrip open-stubs(MOS).Two independent passbands can be realized by using the fundamental mode of two QMSIW resonators and the quasi-TEM mode of a pair of MOS resonators.The experimental results show that the central frequencies of the dual passband filter are located at 5.39 GHz and 10.12 GHz with 3 dB bandwidth of 11.48% and 4.34% respectively.Furthermore,model cross coupling and slot hybrid coupling were used to produce three transmission zeros at 6.78 GHz,8.75 GHz and 11.68 GHz respectively,which significantly improve the selectivity and stopband attenuation of the proposed filter.The effective overall size is about 0.63λ_(g)×0.34λ_(g),which is 75% smaller than that of the traditional ones.Well agreement between the simulation and measurement validates the feasibility of the designed filter.