The purpose of this paper is to propose a miniaturized tri-band bandstop filter that finds application in a modern dense communication system where size and multi-band plays a vital role.,In this paper, the authors propose a miniaturized tri-band microstrip bandstop filter which combines the conventional bandstop filter and spur microstrip line structures such that this design achieves tri-band operation at 1.8 GHz and 3 GHz. The overall length of the microstrip filter is found to reduce from 126 to 45 mm because of introduction of spur lines and via-hole grounding. The addition of spur lines replaces two resonators, introduces two additional resonant frequencies and enhances the −6 dB bandwidth of the center frequency by 14 %.The addition of via-holes in each resonator reduces its length into half of its original length, thereby reducing filter size.,Resonance occurs at three different frequencies 1.8, 2.4 and 3 GHz. The filter size reduces from 126 to 45 mm, and the −6 dB rejection bandwidth of center frequency improves by 14 %.,The overall filter size is reduced by 65% and it resonates at three different frequencies 1.8, 2.4 and 3 GHz with an improved bandwidth of 10 % around the center frequency.

中文翻译：

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使用支线微带线和通孔接地的小型化三频带阻滤波器设计

本文的目的是提出一种小型化三频带阻滤波器，该滤波器适用于现代密集通信系统，其中尺寸和多频起着至关重要的作用。,在本文中，作者提出了一种小型化三频微带带阻滤波器滤波器结合了传统的带阻滤波器和支线微带线结构，因此该设计可在 1.8 GHz 和 3 GHz 下实现三频操作。由于引入了支线和通孔接地，微带滤波器的总长度从 126 毫米减少到 45 毫米。添加支线取代了两个谐振器，引入了两个额外的谐振频率，并将中心频率的 -6 dB 带宽提高了 14%。在每个谐振器中添加通孔将其长度减少到原来长度的一半，从而减小滤波器尺寸。共振发生在三个不同的频率 1.8、2.4 和 3 GHz。滤波器尺寸从 126 mm 减小到 45 mm，中心频率的 −6 dB 抑制带宽提高了 14%。整体滤波器尺寸减小了 65%，并在 1.8、2.4 和 3 GHz 三个不同频率下谐振，具有中心频率附近的带宽提高了 10%。