This study presents a wideband bandpass filter (WBBPF) with wide and high stopband suppression by loading a stepped‐impedance resonator (SIR). The prototype of WBBPF is composed of an inverted π‐shaped resonator with T‐shaped resonator and open stub loaded, centrally. Odd‐/even‐mode analysis technique is employed to characterize the resonant properties of this prototype. Then, a SIR is loaded to this filter, asymmetrically, to improve the out‐of‐band performance. For experimental validation, a WBBPF is designed, fabricated, and tested. The measurement results show that the center frequency of WBBPF is located at 5.095 GHz, and the 3‐dB fraction bandwidth is about 71%. Plus, the out‐of‐band suppression with 30‐dB rejection level can be extended to 18.17 GHz.

中文翻译：

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使用非对称负载步进阻抗谐振器设计具有高阻带和宽带阻带的宽带带通滤波器

这项研究提出了一种通过加载步进阻抗谐振器（SIR）来抑制宽带和高阻带的宽带带通滤波器（WBBPF）。WBBPF的原型由一个倒置的π形谐振器和T形谐振器组成，并在中央装有开放式短截线。奇/偶模分析技术用于表征该原型的共振特性。然后，将SIR非对称地加载到此滤波器，以提高带外性能。为了进行实验验证，对WBBPF进行了设计，制造和测试。测量结果表明，WBBPF的中心频率位于5.095 GHz，3-dB分数带宽约为71％。另外，具有30 dB抑制水平的带外抑制可以扩展到18.17 GHz。