提出一种新型的宽阻带基片集成波导(substrate integrated waveguide, SIW)滤波器. 该滤波器采用直角耦合结构, 在上阻带产生两个传输零点(transmission zeros, TZs), 分别位于两个不同的二次模(TE102/TE201) 谐振频率附近. 为了进一步提高滤波器的阻带特性, 在SIW的上层金属面蚀刻两个矩形槽. 测量结果表明, 该滤波器中心频率10 GHz处的插入损耗为1.9 dB, 通带内回波损耗大于20 dB. 阻带抑制大于20 dB 的频段为10.518.8 GHz, 有效抑制了二次谐波响应. 相比传统SIW 带通滤波器, 阻带宽度增加了48%. 实测结果与仿真结果吻合良好.
A wide stopband filter based on substrate integrated waveguide (SIW) is proposed. Using a right-angle coupling structure, the filter has two transmission zeros (TZs) in the upper stopband. These TZs are located near the resonant frequencies of the two different second-order modes (TE102/TE201), respectively. To further improve the stopband performance, two rectangular slots are etched on the top metal layer of the SIW. The insertion loss is approximately 1.9 dB at the center frequency of 10 GHz. The return loss in the passband is more than 20 dB. The stopband attenuation within 10.518.8 GHz is better than 20 dB, and the second harmonic response is effectively inhibited. Compared with the traditional bandpass filter based on SIW, the stopband bandwidth of this filter is widened by 48%. Measured results well agree with numerical simulations.
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