• Title/Summary/Keyword: Fractional bandwidth

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Coplanar Waveguide Bandpass Filter Using the Folded-line Stepped- Impedance Restorator (접힌 스텝 임피던스 공진기를 이용한 CPW 대역 통과 여파기)

  • 이진택;이창언;신철재
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.8A
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    • pp.620-625
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    • 2003
  • The coplanar waveguide bandpass filter using folded-line stepped-impedance resonators(SIRs) is proposed. The folded-line SIR has about λ/8 length using the short-circuited end on coplanar waveguide. It make that the bandpass filter has the half size in comparison with general λ/4 SIR filter. In this paper, we derive the equivalent circuit and design the bandpass filter by using that. We design and fabricate the bandpass filter which has 5 GHz center frequency and 3 % fractional bandwidth. The measurement results fur 4-pole folded SIR bandpass filter agreed well with full-wave simulation and equivalent circuit results. The fabricated bandpass filter has a good spurious characteristic, which the harmonic frequency appeared at 2.5f$\_$0/). The proposed folded-line SIR bandpass filter are applicable for MMIC and High-Tc superconducting filters. bandwidth.

Design for Broadband Drive Amplifier of Frequency Split Type using GaAs HBT Process (GaAs HBT 공정을 이용한 주파수 분배 방식의 광대역 구동증폭기 설계)

  • Kim, Minchul;Kim, Junghyun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.3
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    • pp.135-140
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    • 2019
  • In this paper, a frequency split type broadband drive amplifier operating in the L, S and C bands was designed and fabricated. Transistor is difficult to efficiently use when the fractional bandwidth of the drive amplifier is more than 100%, In particular, the characteristics of the driving amplifier are important for operating the power amplifier in which the characteristics of the output power and the efficiency are sensitively changed according to the frequency band. A frequency split methods was applied to maximize the bandwidth of a drive amplifier and to divide the output of the drive amplifier into low band and high band so that the transistor of the power amplifier located at the rear of the drive amplifier can be efficiently used. The designed drive amplifier was fabricated in GaAs HBT technology and 9-layer SiP, and verified by the measurements. The fabricated drive amplifier shows a gain of more than 8 dB and an output power of more than 15 dBm in the operating frequency range.

Low-Profile Omni-Directional Microstrip Antenna Using Wired Ground Structure For Observation Munition (정찰포탄용 접지선 구조를 이용한 평판형 무지향성 마이크로스트립 안테나)

  • Pyo, Seongmin
    • Journal of IKEEE
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    • v.23 no.3
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    • pp.1112-1115
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    • 2019
  • This paper proposes a novel low-profile omni-directional microstrip antenna to mount on the deployable wing of the observation munition. The proposed antenna is designed on seven hexagonal resonators in a quasi-circular array to achieve a monopolar radiation pattern with a thin substrate. By employing the mesh ground structures, the resonant frequencies and impedance bandwidths of the proposed antenna is investigated. To verify the feasibility of the mesh ground structure, the thin ground wire width is investigated theoretically for improving the 3-dB fractional bandwidth, realized antenna gain and quality-factor. The proposed antenna demonstrates a good monopolar radiation in good agreement with the simulation results. The implemented prototype shows the measured bandwidth of 326 MHz with respect to 5.65% centered at 5.77 GHz and realized gain of 5.49 dBi at 5.84 GHz.

A Study on the Long-Run Equilibrium Between KOSPI 200 Index Spot Market and Futures Market (분수공적분을 이용한 KOSPI200지수의 현.선물 장기균형관계검정)

  • Kim, Tae-Hyuk;Lim, Soon-Young;Park, Kap-Je
    • The Korean Journal of Financial Management
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    • v.25 no.3
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    • pp.111-130
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    • 2008
  • This paper compares long term equilibrium relation of KOSPI 200 which is underling stock and its futures by using general method fractional cointegration instead of existing integer cointegration. Existence of integer cointegration between two price time series gives much wider information about long term equilibrium relation. These details grasp long term equilibrium relation of two price time series as well as reverting velocity to equilibrium by observing difference coefficient of error term when it renounces from equilibrium relation. The result of this study reveals existence of long term equilibrium relation between KOSPI200 and futures which follow fractional cointegration. Difference coefficient, d, of 'two price time series error term' satisfies 0 < d < 1/2 beside bandwidth parameter, m(173). It means two price time series follow stationary long memory process. This also means impulse effects to balance price of two price time series decrease gently within hyperbolic rate decay. It indicates reverting speed of error term is very low when it bolts from equilibrium. It implies to market maker, who is willing to make excess return with arbitrage trading and hedging risk using underling stock, how invest strategy should be changed. It also insinuates that information transition between KOSPI 200 Index market and futures market does not working efficiently.

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Design of wide-band slot loop antenna by using dual offset-fed (이중 오프셋 급전을 이용한 광대역 슬롯 루프 안테나의 설계)

  • 조영빈;나종덕;전계석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.11A
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    • pp.912-920
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    • 2003
  • This paper is about the design of a small wide-band slot loop antenna, which consists of dual offset-fed and rectangular loop within the slot on a substrate. The proposed antenna is a novel structure generating a multi-resonances due to three geometrical resonance structures. The impedance matching of this antenna can be accomplished by changing the offset position of dual-fed at resonance frequencies. In this experiment, the slot of a fabricated antenna has a center frequency of 6.755㎓, 12.5mm${\times}$50mm in size and the rectangular loop has 10.5mm${\times}$27.5mm in size. The measured result is fractional bandwidth 63.21% with VSWR 2:1, which is agreed with the simulated result within 5% of error, and the maximum antenna gain is 7.42㏈i.

Ultra Wideband Bandpsss Filter Design using the CRLH Transmission Line (CRLH 전송선로를 이용한 초광대역 대역통과 필터의 설계 및 구현)

  • Kim, Gi-Rae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.10
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    • pp.2233-2238
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    • 2013
  • A novel design method of ultra wideband based on the composite right-/left handed (CRLH) transmission line is presented in this paper. Defected ground structure and microstrip interdigital coupler are used to implement the CRLH transmission line. The proposed CRLH transmission line in this paper have composite characteristics of low pass filter and high pass filter, also it has good advantages of low insertion loss and ultra wide passband characteristics. The structure with different cell number are studied, and the UWB filter using 3-cell CRLH transmission line is fabricated and measured, which shows a good agreement between simulated and measured results. It has center frequency of 5 GHz, fractional bandwidth of 105 %, and insertion loss of 0.7 dB at center frequency.

Design of a Bandpass Filter using Two Layer Microstrip Structure (두 층 마이크로스트립 구조를 이용한 대역통과 여파기 설계)

  • 천동완;박정훈;신철재
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.3
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    • pp.18-24
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    • 2003
  • The resonator using two layer microstrip structure was proposed and the bandpass filter was designed using this resonator in this paper. The proposed resonator structure is constructed by placing a U-shape of resonator in the first layer and then placing a broadside coupling strip in the second layer just above of the U-shape of resonator's edge part. Because these structure has various design parameters than general single layer coupled line structure, filter design is more flexible. In this paper, the narrow band filter was designed using multi-layer structure that had been applied to broadband filter because it's high coupling nature. The filter was designed to have 4MHz center frequency and 3 % fractional bandwidth, and finally confirmed that can be realizable narrow band filter by using multi-layer structure through fabrication and measurement.

A Dual-Band Compact Folded Patch Antenna (이중 대역 소형 평면 패치 안테나)

  • 김태영;정종호;박동국;박익모
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.1
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    • pp.47-53
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    • 2003
  • In this paper we proposed a novel dual-band compact folded patch antenna with the same linear polarizations and high isolation characteristic between the two frequency range. The antenna is loaded with a high permittivity dielectric material in order to reduce the antenna size and open circuit stubs are used in order to broaden the bandwidth. The fractional bandwidths of the optimized antenna with demensions 4 mm${\times}$3 mm${\times}$5 mm are 3.0 % at 5.6 GHz band and 2.8 % at 5.8 GHz band, respectively. The isolation characteristic between the two ports is less than -26 dB within the operating frequency range.

Dual-Band Stop Filter Using Metamaterial TLs (Metamaterial 전송선을 이용한 이중 대역 저지 필터)

  • Oh, Hee-Seok;Nam, Sang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.2
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    • pp.124-128
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    • 2009
  • This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is $30{\times}15\;mm$, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.

A Design on the Four-Horn Triple-Mode Type Monopulse Feeder at X-Band (X-대역 4혼 삼중 모드 모노펄스 급전기 설계)

  • Kim, Chan-Hong;Kim, Seung-Gak
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.5
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    • pp.528-536
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    • 2010
  • A monopulse feeder gives the most important impact upon the radiation pattern characteristics of a multi-function radar or a tracking radar which uses the space feed. It is described that the triple-mode type monopulse feeder which possesses the optimum aperture illumination for three monopulse channels is designed and measured in this paper. The measured results show that the designed feeder has not only the characteristics of the optimum aperture illimination in each channel and also very low return loss over the 10 % of fractional bandwidth at X-band. This means that the feeder provides the antenna system with low sidelobe level and high monopulse slope characteristics.