基于双层SIW结构的二阶混合耦合滤波器

Second Order Mixed Coupling Filter Based on Double-layer SIW Structure

设计了一款基于SIW结构的二阶双层混合耦合滤波器,通过在上下谐振腔的公共金属面上设计两个对称圆孔的方法实现了电磁混合耦合,使滤波器在不需要交叉耦合结构的情况下就可以拥有十分靠近通带且灵活可调的传输零点,提高了滤波器的选择性,与平面结构的混合耦合SIW滤波器相比,具有更小的尺寸。为了证实上述结构的有效性,设计了一款工作频率在5.8GHz、3dB相对带宽1.3%、传输零点处于5.9GHz的滤波器,滤波器的介质基板采用的是Rogers 4003,滤波器实测结果与仿真结果基本一致。

A second order mixed coupling filter based on double-layer SIW structure was designed.The electromagnetic mixed coupling was realized by two symmetrical circular holes located on the common metal plane between the upper and lower resonant cavities.With no use of the cross coupling structure the filter can gain a transmission zero that is very close to pass band and flexible adjustable.Compared with the planar mixed coupling SIW filter,the proposed filter has a smaller size.The transmission zero improves the selectivity of the filter.To validate the reliability of the proposed structure,a two-order band pass filter with fractional bandwidth(FBW)of 1.3% at 5.8GHz and a transmission zero at 5.9GHz is designed and fabricated on Rogers-4003 substrate.Measured results and simulated ones are basically consistent.