• Title, Summary, Keyword: low pass filter

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Fabrication of high-temperature superconducting low-pass filter for broad-band harmonic rejection (광대역 고조파 제거를 위한 고온초전도 저역통과필터의 제작)

  • Han, Seok-Gil;Kang, Gwang-Yong;Ahn, Dal;Suh, Jun-Seok;Choi, Chun-Geun;Kim, Sang-Hyeon;Kwak, Min-Hwan
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.193-196
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    • 2000
  • A new type low-pass filter design method based on a coupled line and transmission line theory is proposed to suppress harmonics by attenuation poles in the stop band. The design formula are derived using the equivalent circuit of a coupled transmission line. The new low-pass filter structure is shown to have attractive properties such as compact size, wide stop band range and low insertion loss. The seventh-order low-pass filter designed by present method has a cutoff frequency of 0.9 CHz with a 0.01 dB ripple level. The coupled line type low-pass filter with strip line configuration was fabricated by using a high-temperature superconducting (HTS : YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin film on MgO(100) substrate. Since the HTS coupled tine type low-pass filter was proposed with five attenuation poles in stop band such as 1.8, 2.5, 4, 5.5, 6.2 GHz. The fabricated low-pass filter has improved the attenuation characteristics up to seven times of the cutoff frequency.

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A Compact Lumped-Element Low-Pass Filter with Transmission Zeros

  • Lee, Byoung-Hwa;Park, Sang-Soo
    • Journal of electromagnetic engineering and science
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    • v.3 no.1
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    • pp.35-38
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    • 2003
  • In this paper, compact lumped-element low-pass filter structure with two transmission zeros at second and third harmonics is presented. The use of lumped-elements and transmission zeros can provide the advantages of compact size, sharp cutoff and wide stop-band frequency response. The proposed low-pass filter is a modified Chebyshev low-pass filter type and is implemented by the use of low temperature co-fired ceramic (LTCC) technology. This filter has been verified by both simulation and experiment. The simulated and experimental results agree very well.

Design of Low-Pass Type Inverter: UWB Band-Pass Filter with Low Spurious Characteristics

  • Cho, Young-Ho;Choi, Moon-Gyu;Yun, Sang-Won
    • Journal of electromagnetic engineering and science
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    • v.11 no.2
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    • pp.83-90
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    • 2011
  • In this paper, we present the design method for a low-pass type inverter, which can effectively suppress the spurious response associated with band-pass filters. The inverter has a length of ${\lambda}/4$ and employs not only a stepped-impedance configuration but also asymmetrical and bending structures in order to improve frequency selectivity and compactness. The inverter is applied as an impedance/admittance inverter to the ultra-wideband (UWB) band-pass filter. The UWB band-pass filter configuration is based on a stub band-pass filter consisting of quarter-wavelength impedance inverters and shunt short-circuited stubs ${\lambda}/4$ in length. The asymmetrical stepped-impedance low-pass type inverter improves not only the spurious responses, but also the return loss characteristics associated with a UWB band-pass filter, while a compact size is maintained. The UWB band-pass filter using the proposed inverters is fabricated and tested. The measured results show excellent attenuation characteristics at out-band frequencies, which exceed 18 dB up to 39 GHz. The insertion loss within the pass-band (from 3.1 to 10.6 GHz) is below 1.7 dB, the return loss is below 10 dB, and the group delay is below 1 ns.

The Characteristics of Computer-Generated Holographic Optical Low-Pass Filter (컴퓨터로 설계한 홀로그램 광 저대역 필터의 특성 분석)

  • 김인길;고춘수;임성우;오용호;이재철
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.12S
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    • pp.1261-1267
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    • 2003
  • Since the grating optical low-pass fillet degrades the resolution of images, we developed a hologram optical low-pass filter that show low degradation of the image and studied its characteristics. We designed the hologram that divides input beam into circular shaped 21 beams with a Monte-Carlo based hologram generation program and calculated its MTE characteristics to compare it with that of a grating filter. The hologram was manufactured through the optical lithography process and attached to a digital imaging device (Zoran 732212) for measurement. The moirfiltering is compared with zone plate images and the resolution loss is measured with USAF resolution chart. The hologram optical low-pass filter showed better characteristics in both moly filtering and resolution.

A Ultra-Wideband Bandpass Filter Using DGS structure (DGS구조를 이용한 초광대역 대역통과 여파기)

  • Jung, Seung-Back;Yang, Seung-In
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.5
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    • pp.162-167
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    • 2009
  • In this paper, we present a compact Ultra-Wideband band-pass filter using a high-pass filter and low-pass filter. The structure of our proposed band-pass filter is very simple and the DGS(Defected Ground Structure) structure is used to get the low-pass filter characteristic. Our proposed band-pass filter can be much smaller than a cascaded filter. As a result of measurement the insertion loss is less than 0.5dB throughout the pass-band of $2.1GHz{\sim}10.56GHz$, the return loss is more than 20dB and the group delay maximum variation is 0.23ns from 0.12ns to 0.35ns.

A Novel Design of Compact Low-Pass Filter and Its Equivalent Circuit Model

  • Li, Rui;Kim, Dong-Il;Choi, Chang-Mook;Song, Young-Man
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.79-84
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    • 2006
  • A novel design of compact low-pass filter based on microstrip structure and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

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Compact Low-Pass Filter with Sharp Skirt Characteristics and Broad Stopband

  • Li, Rui;Kim, Dong-Il;Choi, Chang-Mook
    • Journal of Navigation and Port Research
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    • v.30 no.7
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    • pp.607-610
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    • 2006
  • A new compact microstrip low-pass filter and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

The Current and Power Waveform Improvement of an AC Motor with Low Pass LC Filter Driven by a Digital Bridge Inverter(I) (디지탈 브리지형 인버터로 구동되는 저역통과 LC 필터를 가진 교류전동기의 전류 및 전력의 파형 개선 (I))

  • 정주윤;박진길
    • Journal of the Korean Society of Marine Engineering
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    • v.19 no.3
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    • pp.107-118
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    • 1995
  • The characteristics of the current waveforms and 3$\Phi$ power waveforms of the variable speed 3$\Phi$ AC motor system driven by the single-pulse PWM investigated in this paper. The system is composed of a digital bridge inverter and low pass LC filter. It is confirmed that current waveforms and 3$\Phi$ power waveforms can be improved by utilizing the high order low pass LC filter than that of lower order through computer simulation. Also, we propose the low pass LC filter revised from the conventional LC filter.

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A Design of High Temperature Superconducting Low-Pass Filter for Broad-Band Harmonic Rejection (광대역 고조파 제거용 고온초전도 저역통과 필터의 설계)

  • Kwak, Min-Hwan;Kim, Sang-Hyun;Ahn, Dal;Han, Seok-Kil;Kang, Kwang-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.78-81
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    • 2000
  • A new type low-pass filter design method based on a coupled line and transmission line theory is proposed to suppress harmonics by attenuation poles in the stop band The design formula are derived using the equivalent circuit of a coupled transmission line. The new low-pass filter structure is shown to have attractive properties such as compact size, wide stop band range and low insertion loss. The seventh-order low-pass filter designed by present method Ins a cutoff frequency of 0.9 GHz with a 0.01 dB ripple level. The coupled line type low-pass filter with stripline configuration was fabricated by using a high-temperature superconducting (HTS ; $YBa_2Cu_3O_{7-x}$) thin film on MgO(100) substrate. Since the HTS coupled line type low-pass filter was proposed with five attenuation poles in stop band such as 1.8, 2.5, 4, 5.5, 62 GHz. The fabricated low-pass filter has improved the attenuation characteristics up to seven times of the cutoff frequency Bemuse of good rejection of the spurious signals and harmonics, our low-pass filter is applicable to mobile base station systems such as cellular, personal communication systems and international mobile telecommunication(IMT)-2000 systems.

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A Low-pass Filter with Wide-stop Band Using Radial-shaped Open Stub (광대역의 저지대역을 갖는 부채꼴 형태의 개방형 스터브를 이용한 저역통과 여파기)

  • Yoon, Ki-cheol;Kim, Seong-cheol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.7
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    • pp.1237-1242
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    • 2016
  • In this paper, the low pass filter with harmonics suppression and rejection using parallel coupled-line and radial type open stub is presented. And the resultant characteristic of the proposed low pass filter is that the harmonics are suppressed and rejected in wide bandwidth due to the parallel coupled-line structure. The open stub of a low pass filter is constructed in radial type which can be used to adjust the size of filter. The size of the proposed low pass filter is $6.98{\times}7.60mm2$ and the cut off frequency is 2.45 GHz. And the filter is economical in unit cost and can be constructed easily and has the merit of mass product because the filter is composed of distributed element. Also, the widely rejected harmonics is 128 % in the bandwidth and the insertion and return losses of the low pass filter are 1.07 dB and 19.5 dB, respectively.