ABSTRACT

In this article, a high-selectivity double-mode substrate integration waveguide bandpass filter utilizing modified parallel coupled microstrip lines (MPCML) is presented. The designed method is analyzed in detail. Six metal vias are designed to perturb TE-₁₀₁ mode and TE-₁₀₃ mode. The resonant frequency of the perturbed TE-₁₀₁ mode is shifted to high frequency, close to that of TE-₁₀₂ mode, which caused the formation of passband. The resonant frequency of the perturbed TE-₁₀₃ mode is shifted to high frequency, improving out-of-band performance. Simultaneously, the coplanar waveguide structure is used to adjust the external quality factor. Two rectangular slotlines are introduced to adjust center frequency and bandwidth slightly. Two rectangular stubs are designed for better source and load matching. Three transmission zeros (TZs) are obtained to improve the selectivity. The designed MPCML promotes the generation of TZs. Another TZ is obtained by the coupling between TE-₁₀₂ mode and TE-₁₀₃ mode. The designed filter operates at 14.4 GHz with bandwidth of 800 MHz. The measured return loss is better than 15 dB, and the minimum insertion loss is 1.60 dB. The measurement is agreed with the simulation.

摘要

在本文中，提出了一种利用改进的平行耦合微带线 (MPCML) 的高选择性双模基板集成波导带通滤波器。详细分析了所设计的方法。六个金属通孔设计用于干扰 TE- ₁₀₁模式和 TE- ₁₀₃模式。被扰动的TE- ₁₀₁模的谐振频率向高频偏移，接近TE- ₁₀₂模的谐振频率，导致通带的形成。被扰动的 TE- ₁₀₃的谐振频率模式转移到高频，提高带外性能。同时，共面波导结构用于调整外部品质因数。引入两条矩形槽线，对中心频率和带宽进行微调。两个矩形短截线设计用于更好的源和负载匹配。获得三个传输零点 (TZ) 以提高选择性。设计的 MPCML 促进了 TZ 的生成。另一个 TZ 是通过 TE- ₁₀₂模式和 TE- ₁₀₃模式之间的耦合获得的。设计的滤波器工作频率为 14.4 GHz，带宽为 800 MHz。实测回波损耗优于15dB，最小插入损耗为1.60dB。测量与模拟一致。