• Title/Summary/Keyword: Band-Stop

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Design of a Band-Stop Filter for UWB Application (UWB용 대역 저지 필터 설계)

  • Roh Yang-Woon;Hong Seok-Jin;Chung Kyung-Ho;Jung Ji-Hak;Choi Jae-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.2 s.105
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    • pp.89-94
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    • 2006
  • A compact microstrip band-selective filter for ultra-wideband(UWB) radio system is proposed. The filter combines the traditional short-circuited stub highpass filter and coupled resonator band-stop filter on both sides of the mitered 50-ohm microstrip line. To realize the pseudo-highpass filtering characteristic over UWB frequency band(3.1 GHz to 10.6 GHz), a distributed highpass filter scheme is adopted. Three coupled resonators are utilized to obtain the band stop function at the desired frequency band. By meandering the coupled resonators, there is $29\;\%$ size reduction in footprint compared to the traditional band-stop filter using L-shaped resonators. The measured results show that the filter has a wide passband of $146.7\;\%$(2.1 GHz to 10.15 GHz) with low insertion loss and the stop band of $10.04\;\%$(5.2 GHz to 5.75 GHz) for 3-dB bandwidth. The measured group delay is less than 0.7 ns within the passband except the rejection band.

Design Technique Using Bypass Capacitor to Improve Antenna Efficiency of Inverted-F Antenna with Band Stop Matching Circuit (Band Stop Matching Circuit이 적용된 Inverted-F Antenna의 Bypass Capacitor를 이용한 안테나 효율 향상 기법)

  • Bae, Jang Hwan;Choi, Woo Cheol;Lim, Seonho;Yoon, Young Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.1
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    • pp.1-7
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    • 2019
  • In this paper, a design technique using a bypass capacitor is proposed to improve the antenna efficiency of an inverted-F antenna (IFA) with a band stop matching circuit (BSMC). The proposed antenna operates in the LTE bands 26 and 5(814~ 894 MHz). The bandwidth of the IFA is expanded from 803~863 MHz to 800~888 MHz using the impedance change caused by the BSMC. To enhance the antenna efficiency in the expanded frequency band, the bypass capacitor is applied to the IFA with the BSMC. The bypass capacitor improves the efficiency of the antenna by reducing the current variation of the IFA with the BSMC. The proposed antenna has a bandwidth of 804~895 MHz and the antenna efficiency increases by more than 10 % in the extended frequency band by using the bypass capacitor.

Wideband Bandstop filter Using Dual Spurline and Coupling Open Stubs (이중 스퍼라인과 커플링 오픈스터브를 이용한 광대역 대역저지 필터)

  • Lee, Hyun-Seung;Choi, Jee-Hwan;Kim, Choul-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.2
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    • pp.1-5
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    • 2017
  • In this paper, we propose a wideband band-stop filter (BSF) in order to extend the stopband of the band-stop filter using a symmetric dual spurline and the coupled open stub. First, we know that the symmetric dual spurline structure is advantageous in widening the stopband, as compared to the asymmetric dual spurline structure. So we designed a band-stop filter that combines the electrically coupled open stub (ECOS) band-stop filter with a symmetric dual spurline. We can greatly extend the stopband, when it is combined with the dual spurline and electrically coupled open stub on a microstrip transmission line, without any size increment. The stopband of the proposed band-stop filter is extended by approximately 244% (rejection depth: -20 dB) compared with a band-stop filter without a dual spurline.

The Design of Microstrip Band-Selective Filter with Narrow Stopband for UWB Application (협대역 저지 특성을 가지는 UWB용 마이크로스트립 필터 설계)

  • Roh, Yang-Woon;Hong, Seok-Jin;Jung, Kyung-Ho;Jung, Ji-Hak;Choi, Jae-Hoon
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2005.11a
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    • pp.7-12
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    • 2005
  • A compact microstrip band-selective filter for ultra-wideband (UWB) radio system is proposed. The filter combines the traditional short-circuited stub highpass filter and coupled resonator bandstop filter on both sides of the mitered 50-ohm microstrip line. To realize the pseudo-highpass filtering characteristic over UWB frequency band (3.1 GHz to 10.6 GHz), a distributed highpass filter scheme is adopted. Three coupled resonators are utilized to obtain the band stop function at the desired frequency band. By meandering the coupled resonators, there is 29% reduction in footprint compared to the traditional bandstop filter using L-shaped resonators. The measured results show that the filter has a wide passband of 146.7 % (2.1 GHz to 10.15 GHz) with low insertion loss and the stop band of 7.42 % (5.32 GHz to 5.73 GHz) for 3-dB bandwidth. The measured group delay is less than 0.7 ns within the passband except the rejection band.

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Dielectric Band-Pass Filter with Attenuation Poles at Desired Frequencies

  • Lee, Moon-Que
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.6
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    • pp.268-271
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    • 2004
  • An analytic design formula is proposed for a TEM mode dielectric bandpass filter with attenuation poles at desired frequencies in the stop band. In order to sustain the constant ripple in the passband due to attenuation poles, the initial resonant frequencies of the various resonators adopted in a filter with attenuation poles are newly calculated. The proposed design theory is verified by designing various bandpass filters with attenuation poles in the stop band.

Compact Spatial Triple-Band-Stop Filter for Cellular/PCS/IMT-2000 Systems

  • Kim, Dong-Ho;Yeo, Jun-Ho;Choi, Jae-Ick
    • ETRI Journal
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    • v.30 no.5
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    • pp.735-737
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    • 2008
  • We propose a novel spatial multi-band-stop filter using modified multiple loop array elements to block electromagnetic waves or signals of mobile phones in public facilities. It operates at the following frequency bands: Korean cellular (824 MHz to 894 MHz), Personal Communication Service (PCS) (1.75 GHz to 1.87 GHz), and IMT-2000 (1.92 GHz to 2.17 GHz). Two frequency selective surfaces with modified multiple-loop elements are printed on the top and bottom of a pair-glass pane, which is a pair of glass panes with an air gap between them. A modified multiple-loop element with a meander line is used to make the size of the filter compact. The simulated and measured results show good agreement, which confirms the usefulness of the proposed tri-band spatial filter.

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Dual-band Gysel Power Divider based on Filter Conversion Technique (여파기 변환 기법을 이용한 이중대역 Gysel 전력 분배기)

  • Yoo, Jae-Hyun;Kim, Young
    • Journal of Advanced Navigation Technology
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    • v.17 no.1
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    • pp.33-38
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    • 2013
  • In this paper, we present the design and measured performances of an dual-band Gysel power divider based on band-stop characteristic. After the Gysel divider is designed by lumped elements at single operating frequency, and then using filter conversion technique the lumped elements were changed a band-stop characteristic with dual-band characteristics. The features of this design method are that ${\lambda}/4$ transmission line by replacing lumped elements suppressed harmonic characteristics and also can reduce the size. To validate of the proposed power divider, the divider has been designed and measured at 880 MHz and 1650 MHz dual frequencies. The measured performances of the Gysel divider agree with prediction results at two frequencies.

Optimization of band-stop filter in coaxial line (동축선로내 대역억제필터의 최적화)

  • 정봉식
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.1
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    • pp.97-103
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    • 2000
  • In this paper band-stop filters that reject the undesired 3th and/or 5th harmonics generated from high frequency generator are analyzed using equivalent circuit concept, and optimized using iterative optimization algorithm. The length of the band-stop filter is setup initially a quarter of a wavelength of the harmonic, but initial filter structure is exactly unable to cutoff the harmonics because of the fringing effect at the discontinuous boundary. To reduce the mismatch between the cutoff frequency and the harmonics, iterative LMA(Levenberg-Marquardt Algorithm) is introduced and band-stop filters in coaxial line are optimized.

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Design of a UWB Antenna with Band-Notch Function

  • Fanli, Zeng;Lee, Jae-Won;Kim, Chul-Hee;Choi, Jae-Hoon
    • Journal of electromagnetic engineering and science
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    • v.10 no.1
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    • pp.39-44
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    • 2010
  • In this paper, a compact wideband antenna with a band-notch function is proposed. It operates over the UWB band with a band-stop characteristic. To increase the impedance bandwidth, a ring-shaped radiator is used. By attaching a circular stub to the ring-shaped radiator, the band-notch performance is obtained. The proposed antenna operates over a frequency range from 2.7 GHz to 11 GHz to satisfy the 10-dB return-loss requirement and provides band-stop performance in the frequency band from 5.15 GHz to 6.1 GHz. Experimental results reveal that the proposed antenna exhibits good radiation performance and is suitable for UWB applications.

Dispersion Characteristics of Optical Waveguide with Periodic Blazed Grating Profile (주기적인 Blazed 격자로 구성된 광 도파로의 분산 특성)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.2
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    • pp.195-200
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    • 2020
  • Leakage and Bragg condition of optical waveguides with blazed grating profile are evaluated in detail by using novel and rigorous modal transmission-line theory (MTLT) based on eigenvalue problem. The blazed waveguides classified as symmetric, sawtooth and asymmetric gratings occur leaky-wave stop-band at Bragg conditions and anomalies based on Rayleigh condition near Bragg conditions. Furthermore, DFB properties of blazed waveguides at Bragg conditions are analyzed by applying longitudinal equivalent transmission-line with characteristic impedance of periodic grating. The numerical results show that the reflected power of DFB waveguides is maximized at Bragg conditions in which leaky-wave stop-bands occur.