非谐振型结构的复合左右手带通滤波器小型化设计

Design of Compact CRLH Bandpass Filter Based on Structure of CSRR-SIW

提出了一种非谐振型结构的复合左右手带通滤波器,可应用于WLAN频段。该结构只采用一个复合左右手传输线单元,单元内部的交指结构提供等效左手电容,过孔结构提供等效左手电感,单元内部存在交叉耦合。通过调整交叉耦合电容和左右手参数,可产生2个可控传输零点并缩减尺寸。通过添加DGS缺陷地结构,能进一步优化滤波器性能。经过仿真优化最终设计出一款具有较高选择性、较好带外抑制性能的带通滤波器。实测结果显示:滤波器工作频率为5.98 GHz,3 dB带宽为940 MHz,带内插损最大值为1.59 dB。相比传统滤波器设计,该结构大幅度减小了器件体积。

A composite left-right bandpass filter with non-resonant structure is proposed.Only one compound left-right transmission line element is adopted in this structure.The interfingered structure within the unit provides the equivalent left-handed capacitance,the via structure provides the equivalent left-handed inductance,and there is cross-coupling in the unit.By adjusting cross-coupling capacitance and left-right parameters,two controllable transmission zeros can be generated and the dimensions can be reduced.By adding DGS defected structure,the performance of the filter can be further optimized.Through simulation and optimization,a bandpass filter with high selectivity and good out-of-band suppression performance is designed.The measured results show that the working frequency of the filter is 5.98 GHz,the 3 dB bandwidth is 940 MHz,and the maximum value of interpolation loss is 1.59 dB.Compared with the traditional filter design,the structure greatly reduces the device volume.