基于CSRR-SIW结构的复合左右手带通滤波器小型化设计

提出了一种基于互补开口谐振环-基片集成波导（complementary split-ring resonator-substrate integrated waveguide，CSRR-SIW）结构的复合左右手带通滤波器，可应用于5G频段。采用互补开口谐振环（complementary split-ring resonator，CSRR）代替传统开口谐振环结构，有效地减小了中心频率，通过改变端口馈电方式展宽了带宽并改善了高频端带外抑制特性。基片集成波导（substrate integrated waveguide，SIW）结构将电磁波限定在一定空间范围内传播，使得该款滤波器较为紧凑。将4个具有左手特性的互补开口谐振环单元加载到带通滤波器中，通过调整优化，可在通带处产生2个传输零点，并进一步缩小滤波器的体积。测试结果显示：滤波器的中心频率为4.92 GHz，3 dB带宽为240 MHz，带内插损最大值为1.7 dB，且在5.88～13.80 GHz的带外抑制大于20 dB。

Design of compact CRLH bandpass filter based on structure of CSRR-SIW

In this paper, a composite right/left handpass filter based on CSRR-SIW (complementary split-ring resonator-substrate integrated waveguide) which can be used in 5G band is proposed. A complementary split-ring resonator (CSRR) is utilized to substitute the traditional structure, and the center frequency is effectively reduced. By changing the feeding mode, the bandwidth of the filter is expanded, and the characteristic of outside band suppression at high frequency is also improved. The SIW (substrate integrated waveguide) structure is designed to limit the propagation of electromagnetic waves in a certain spatial range, and the structure of the filter is more compact. Four complementary split resonant rings with left hand characteristics are added to the filter. By adjustment and optimization, it generates two transmission zeros at the pass band, and the size of the filter is further reduced. The test results show that the central frequency of the filter is 4.92 GHz, the bandwidth of 3dB is 240 MHz, the maximum loss in the band is 1.7 dB, and the out of band suppression of 5.88 GHz~13.80 GHz is greater than 20 dB.