一种具有高抑制特性的小型化SIW滤波器的设计

Design of a miniaturized SIW filter with high suppression characteristics

为有效减小滤波器的损耗及提高其频率选择性,提出了一种具有高抑制特性的小型化基片集成波导(SIW)滤波器。基于隐失模理论,在SIW顶部刻蚀矩形谐振环来实现小型化及滤波特性。通过控制矩形谐振环间的距离,改变其耦合,从而达到控制传输零点的目的,最终在9.48 GHz处产生一个传输零点,其最大衰减量为77.48 dB。该滤波器的有效尺寸约为0.818λ_(g)×0.348λ_(g),中心频率为5.5 GHz,最小插入损耗为0.27 dB,回波损耗优于21.9 dB,带外抑制在6.22~22.3 GHz范围内均大于20 dB,实测与仿真结果基本吻合。该滤波器具有高抑制、小型化和低插损的特性,可用于5G(Sub-6 GHz)无线通信系统中。

To reduce the loss of a filter and improve its frequency selectivity,a miniaturized substrate integrated waveguide(SIW)filter with high rejection characteristics was proposed.The rectangular resonant ring was etched on the top of the SIW based on evanescent mode theory to achieve miniaturization and filtering characteristics.The coupling was tuned by controlling the distance between the rectangular resonant rings.The transmission zero was finally obtained at 9.48 GHz with the maximum attenuation of 77.48 dB.The effective overall size is about 0.818λ_(g)×0.348λ_(g).The central frequency is located at 5.5 GHz with the minimum insertion loss of 0.27 dB,and the return loss is better than 21.9 dB in the working band.Moreover,the 20 dB out-of-band rejection is from 6.22 GHz to 22.3 GHz.The measured results are in good agreement with the simulation results.The filter has such advantages as high out-of-band rejection,miniaturization,and low insertion loss,which make it promising for 5G(Sub-6 GHz)wireless communication systems.