volume | PIER Journals

2020-04-15

Design of Compact Electronically-Tuned Bandpass Filter with Sharp Rejection Skirt Using the Trans-Directional Coupled Line

Xiaojian Guo,

Dr. Xiaojian Guo

School of Information Science and Technology

Dalian Maritime University

China

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Shao-Jun Fang,

Prof. Shao-Jun Fang

Information Engineering College

Dalian Maritime University

China

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Hongmei Liu,

Dr. Hongmei Liu

School of Information Science and Technology

Dalian Maritime University

China

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Zhongbao Wang

Dr. Zhongbao Wang

School of Information Science and Technology

Dalian Maritime University

China

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Progress In Electromagnetics Research Letters, Vol. 90, 127-133, 2020

doi:10.2528/PIERL20020704

Abstract

A compact frequency-tuned bandpass filter (BPF) with sharp rejection characteristic is presented. It is composed of a trans-directional (TRD) coupled line and two short-circuited stubs. By changing the capacitor values of the coupled line and the electrical lengths of the short-circuited stubs, a frequency-tuned BPF with sharp rejection is obtained. For verification, a prototype tuned from 1.0 GHz to 1.6 GHz (46.2%) is designed and fabricated. The measured results show that the proposed structure exhibits the return loss of more than 17 dB, the insertion loss of 1.4 dB, and the 3-dB fractional bandwidth (BW) of 43.2-50%. Sharp rejections are also obtained, agreeing well with the simulation results.

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Xiaojian Guo, Shao-Jun Fang, Hongmei Liu, and Zhongbao Wang, "Design of Compact Electronically-Tuned Bandpass Filter with Sharp Rejection Skirt Using the Trans-Directional Coupled Line," Progress In Electromagnetics Research Letters, Vol. 90, 127-133, 2020.
doi:10.2528/PIERL20020704

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