• Title/Summary/Keyword: Stub Loaded Resonator

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Tri-band Microstrip Bandpass Filter Using Dual-Mode Stepped-Impedance Resonator

  • Liu, Haiwen;Lei, Jiuhuai;Zhao, Yulong;Xu, Wenyuan;Fan, Yichao;Wu, Tiantian
    • ETRI Journal
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    • v.35 no.2
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    • pp.344-347
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    • 2013
  • This letter presents a compact dual-mode tri-band bandpass filter by using a short-circuited stub-loaded stepped-impedance resonator (SIR) and a short-circuited stub-loaded uniform impedance resonator. Also, a hairpin SIR geometry is introduced to miniature the size of this filter while maintaining excellent performance. The use of a short-circuited stub at the central point of the hairpin SIR can generate two resonant modes in two passbands. Its equivalent circuit structure is analyzed by using the even-odd mode theory. For demonstration purposes, a tri-band filter for the applications of the Global Positioning System at 1.57 GHz, Worldwide Interoperability for Microwave Access at 3.5 GHz, and wireless local area networks at 5.2 GHz is designed, fabricated, and measured.

A Tuable Dual-Band Bandpass Filter Design Using Variable Characteristic Transmission Lines (가변 특성 임피던스 전송 선로를 이용한 가변 이중 대역 대역 통과 여파기)

  • Chaudhary, Girdhari;Jeong, Yong-Chae;Lim, Jong-Sik;Kim, Dong-Su;Kim, Jun-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.9
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    • pp.852-857
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    • 2011
  • In this paper, the application of a variable characteristic impedance transmission line that can be used to design a dual-band bandpass filter(BPF) is presented. The proposed filter offers a fixed first frequency passband and a controllable second passband. The tuning of the second passband is achieved by varying the characteristic impedance of and open shunt stub line in a stub loaded resonator(SLR) with the help of a defected ground structure(DGS) transmission line and varactor diodes. In order to validate the proposed structure, a two stage dual-band BPF with three transmission zeros was implemeted and experimentally verified based on its theoretical predictions and simulations.

Quad-Band Bandpass Filter Using Quad-Mode Stub-loaded Resonators

  • Liu, Haiwen;Wang, Xiaomei;Wang, Yan;Li, Shen;Zhao, Yulong;Guan, Xuehui
    • ETRI Journal
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    • v.36 no.4
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    • pp.690-693
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    • 2014
  • Compact multi-band bandpass filters using quad-mode stub-loaded resonators are proposed in this letter. Firstly, a novel approach about the mode-splitting characteristics of the quadruple-mode resonator is investigated, which can provide dual-band behavior. Secondly, a quad-band filter is proposed and designed by cascading two quadruple-mode resonators; the upper one operates at 1.8/2.4 GHz (GSM- and WiMax-band) and the lower one at 1.57/2.1 GHz (GPS- and WCDMA-band). Finally, the proposed filters have been fabricated. Respectable agreement between simulation and measurement verifies the validity of this design methodology.

Design of a Dual-Band Bandpass Filter Using an Open-Loop Resonator

  • Im, Hyun-Seo;Yun, Sang-Won
    • Journal of electromagnetic engineering and science
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    • v.17 no.4
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    • pp.197-201
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    • 2017
  • In this paper, we present a novel design for a dual-band bandpass filter (BPF) based on the conventional second-order, open-loop BPF. By adding series resonant circuits to the open ends of the resonator, we can create two resonant modes from the even and odd modes. One pair of the even and odd modes constitutes the upper passband, while the other pair constitutes the lower passband. By adding another series resonant circuit to the open-loop resonator, we can control the bandwidth of either the upper passband or the lower passband. We can replace the series resonant circuits with simple microstrip line resonators. A dual-band BPF working at both Wi-Fi bands (2.4 GHz and 5.8 GHz bands) is designed based on the proposed method and is tested. The measured and simulated results show excellent agreement.

Compact Dual-Wideband Bandpass Filter with Multimode Resonator

  • Liu, Haiwen;Li, Shen;Guan, Xuehui;Ren, Baoping;Lei, Jiuhuai;Wang, Yan
    • ETRI Journal
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    • v.36 no.1
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    • pp.163-166
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    • 2014
  • A microstrip dual-wideband bandpass filter using a multimode resonator (MMR) is proposed in this letter. The proposed MMR loaded with a T-shaped open-ended stub and a short-ended stub exhibits triple mode characteristics, and a synthesis method is developed to illustrate the wide passband with independently controllable center frequencies and bandwidths. To verify this design methodology, a dual-wideband filter with fractional bandwidths of 19.1% and 27.9% is designed and fabricated. The measured results agree with the simulations.

Microstrip Lowpass Filter with Very Sharp Transition Band and Wide Stopband

  • Hayati, Mohsen;Sheikhi, Akram
    • ETRI Journal
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    • v.33 no.6
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    • pp.981-984
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    • 2011
  • A novel lowpass filter with a very sharp transition band and wide stopband is proposed. The proposed filter is based on T-shaped patches which are etched in symmetrical structures and folded open stub. To obtain a wide stopband, we have used stub loaded semi-circle stepped-impedance structures. By designing the resonator with high inductance and capacitance, a very sharp transition band is achieved. The proposed filter has a 3-dB cutoff frequency at 2.37 GHz and a 40-dB rejection at 2.44 GHz. The stopband with an attenuation level better than -13.2 dB is up from 2.4 GHz to 16 GHz, and consequently we have reached the high and wide rejection in stopband with compact size. Good agreements between the simulated and the measured results are presented.

UWB Bandpass Filter Using Capacitive Coupling with Cross Resonator ("+"자 공진기와 용량성 결합을 이용한 초광대역 대역 통과 여파기)

  • Dong, Thai Hoa;Lee, Jae-Young;Kim, Ihn-Seok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.5
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    • pp.486-493
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    • 2010
  • This article introduces a novel ultra wideband(UWB) bandpass filter(BPF) with sharp roll-off characteristics in stripline structure. The UWB characteristic is basically obtained from capacitive coupled cross resonator. The resonator has ${\lambda}/2$ length. And at the center of the resonator, two stubs are loaded, one is a ${\lambda}/8$ short-circuited stub and the other is a ${\lambda}/8$ open-circuited stub. The two stubs provide two attenuation poles at lower and upper cutoff frequencies. For input and output lines, two identical capacitively coupled lines have been installed to suppress the unwanted signals in the lower and upper stopbands. The filter has been designed for the U.S. UWB band(3.1~10.6 GHz) with two transmission zeros at 2.4 and 11.1 GHz. The filter has been realized with Low Temperature Core-fired Ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results. Insertion loss less than 0.7 dB and return loss better than 14 dB in the pass band have been measured. The group delay in the center frequency is 0.27 ns and the group delay variation within pass band is less than 0.5 ns. The size of the filter is $6{\times}18{\times}0.6\;mm^3$.