A miniaturized high-isolation quadplexer with wide upper-stopband based on open and short stub-loaded multimode-resonator is proposed in this paper. Based on the theory of multimode-resonator and stepped impedance resonator (SIR), the compact quadplexer is designed by using multimode-resonator and SIR. In order to further miniaturize the size of the circuit, the multimode resonator is employed as the common resonator to replace the common matching network of the quadplexer and the SIRs are curved. Equivalent topology circuit is given to analyze and design the quadplexer. Detailed analyses are given according to the equivalent circuits. The proposed compact quadplexer working at central frequencies of 1.8, 2.4, 2.8, and 3.5 GHz with over 40 dB isolation is finally simulated, fabricated, and measured. The measured results agree well with the simulated ones. The total size of the fabricated quadplexer is 0.36 λg × 0.42 λg.

中文翻译：

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具有宽上阻带和高隔离度的紧凑型多模谐振器多路复用器

本文提出了一种基于开路短截线加载多模谐振器的小型化高隔离宽上阻带四工器。基于多模谐振器和阶梯阻抗谐振器(SIR)的理论，利用多模谐振器和SIR设计了紧凑型四工器。为了进一步缩小电路的尺寸，采用多模谐振器作为公共谐振器来代替四工器的公共匹配网络，并且SIR是弯曲的。给出等效拓扑电路对四工器进行分析和设计。根据等效电路进行详细分析。最终仿真、制造和测量了工作在 1.8、2.4、2.8 和 3.5 GHz 中心频率且隔离度超过 40 dB 的所提出的紧凑型四工器。实测结果与模拟结果吻合良好。制造的四工器的总尺寸为 0.36λg × 0.42λG。