An ultra-wideband filtering power divider (FPD) with miniaturized sized is proposed in this article. In order to improve the selectivity of the filter, modified stepped impedance resonators (SIRs) are utilized to generate two transmission zeroes nearby the passband. Moreover, three transmission poles within the passband are introduced with the modified SIR structure and the short-circuit stubs, which can enlarge the bandwidth of the proposed FPD circuit. An equivalent circuit model is built to interpret the mechanism of the presented FPD design. Finally, a prototype of the wideband FPD structure centered at 3.34 GHz is designed, fabricated and tested with 3-dB fractional bandwidth of 95.2%. A sharp selectivity of 52.9 dB/GHz is also observed. The measured results agree well with the simulated predictions.

中文翻译：

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一种改进型三线耦合结构的超宽带锐选择性滤波功分器

本文提出了一种小型化的超宽带滤波功率分配器（FPD）。为了提高滤波器的选择性，使用改进的阶梯阻抗谐振器 (SIR) 在通带附近生成两个传输零点。此外，通过改进的 SIR 结构和短路短截线引入了通带内的三个传输极点，这可以扩大所提出的 FPD 电路的带宽。建立等效电路模型来解释所提出的 FPD 设计的机制。最后，以 3.34 GHz 为中心的宽带 FPD 结构原型被设计、制造和测试，3-dB 分数带宽为 95.2%。还观察到 52.9 dB/GHz 的尖锐选择性。测量结果与模拟预测非常吻合。