• Title/Summary/Keyword: ultra-wide stopband

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A Compact Three Stage Low-Pass Filter with an Ultra-Wide Stopband (초광대역의 저지대역을 갖는 3단 저역통과 필터)

  • 김경훈;정종호;기철식;임한조;박익모
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.3
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    • pp.25-31
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    • 2003
  • In this paper, we proposed a novel compact microstrip lowpass filter with an ultra-wide stopband and a sharp cutoff frequency response. To improve the cutoff response of the conventional filter, the coupling effect between two open stubs is used. The slot on the ground with conventional shunt open stubs plays an important role of increasing the stopband at a high frequency. The combination of these structures gives the filter the characteristics of an ultra-wide stopband with a prominent cutoff sharpness. The fabricated microstrip lowpass filter with the size of 19.2 mm $\times$ 14.9 mm has -3 dB cutoff frequency at 1.1 GHz and -20 dB stopband from 1.5 GHz to over 30 GHz. The insertion loss is less than -0.15 dB in the passband.

Analysis of Novel Approach to Design of Ultra-wide Stopband Microstrip Low-Pass Filter Using Modified U-Shaped Resonator

  • Karimi, Gholamreza;Lalbakhsh, Ali;Dehghani, Khatereh;Siahkamari, Hesam
    • ETRI Journal
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    • v.37 no.5
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    • pp.945-950
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    • 2015
  • A novel microstrip low-pass filter is presented to achieve an ultra-wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U-shaped resonator (which creates two fully adjustable transmission zeroes), a T-shaped resonator (which determines a cut-off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent-circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut-off frequency ($f_c=2.35GHz$) has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure-of-merit of 15,221.

A Compact and High Performance Lowpass Filter using Combined Characteristics of Slot and Open Stub (슬롯과 개방 스터브의 특성을 결합한 소형 저역통과 여파기)

  • 김경훈;김상인;박익모;임한조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.1
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    • pp.36-43
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    • 2004
  • In this paper, we proposed a novel compact microstrip lowpass filter with an ultra-wide stopband and prominent cutoff sharpness using slot on the ground plane and microstrip shunt open stub. The microstrip shunt open stub and slot exhibit the different stopband response. The combined characteristics of these structures gives the ultra-wide stopband characteristics and the coupling effect between slots on the ground plane makes the prominent cutoff sharpness. The fabricated microstrip lowpass filter with the size of 20.1 mm ${\times}$ 18.7 mm has -3 ㏈ cutoff frequency at 1.187 ㎓ and -20 ㏈ stopband from 1.33 ㎓ to over 20 ㎓ and the insertion loss in the passband is less than -0.4 ㏈ form DC to 1 ㎓.

Miniaturized X-Band Metamaterial Filter for the Ultra-Wide Stopband (차단특성의 초광대역화를 위한 X-밴드용 초소형 메타물질구조 여파기)

  • Kahng, Sung-Tek;Lim, Dong-Jin;Jang, Geon-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.12
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    • pp.59-64
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    • 2009
  • In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.

A Lowpass Filter with an Ultra-Wide Stopband and Prominent Cutoff Sharpness (넓은 저지대역과 우수한 cutoff 특성을 갖는 저역통과 여파기)

  • Kim, Kyung-Hoon;Kim, Sang-In;Park, Ik-Mo;Lim, H.
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.352-356
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    • 2003
  • 본 논문에서는 매우 넓은 저지대역과 우수한 cutoff 특성을 갖는 저역통과 여파기를 제안하였다. 접지면 슬롯과 급전면 개방 스터브의 특성을 결합한 기존의 광대역 여파기에서 전송선의 길이를 ${\lambda}_g/4$로 변형함으로써 기존의 여파기보다 더 작은 크기로 넓은 저지대역과 급격한 cutoff 특성을 얻을 수 있었다. 또한 설계한 단위 여파기를 특정 간격로 배열하여 더 깊은 저지대역과 향상된 cutoff 특성을 얻을 수 있었다.

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Design of Cascaded Lowpass Filter using Combination of Stopbands (저지대역의 중첩을 이용한 캐스캐이드 저역통과 여파기의 설계)

  • 김경훈;김상인;박익모;임한조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.7
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    • pp.644-652
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    • 2004
  • In this paper, we designed a cascaded microstrip lowpass filter using the lowpass filters previously proposed. The previously proposed lowpass filters have a ultra-wide stopband and prominent cutoff sharpness using the combined characteristics of slot and microstrip open stub, respectively, and they are catagorized into 2 types by the method that determining their passband characteristics. The first type is determined its passband characteristics by open stub characteristics and the second is by slot characteristics. By cascading these structures with impedance adjustment of each element, the deeper out-of-band rejection and the sharper skirt response were achieved. The fabricated cascaded lowpass filters have -3㏈ cutoff frequencies at 1.035㎓ and 1.286㎓ respectively and -20㏈ stopband is over 20㎓ for both structures.

An Optimal Design of the Compact CRLH-TL UWB Filter Using a Modified Evolution Strategy Algorithm

  • Oh, Seung-Hun;Wu, Chao;Chung, Tae Kyung;Kim, Hyeong-Seok
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.653-658
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    • 2015
  • This paper deals with an efficient optimization design method of a compact ultra wideband (UWB) filter which can improve the characteristics of the filter. The Evolution Strategy (ES) algorithm is adopted for the optimization and modified to suppress the ripple by inserting an additional step to the ES scheme. The algorithm has the ability to control the ripple of an insertion loss in a passband as a modified approach. During the modified ES, a structure of initial shape is changed a lot, while includes the stepped impedance (SI) and the composite right/left handed transmission line (CRLH-TL). And an optimized filter satisfies the UWB specifications on the stopband and passband with an acceptable insertion loss. The filter achieves a much developed shape, the size of $15{\times}14mm$, the 3dB bandwidth from 2.7 to 10.8GHz, the flat insertion-loss less than 1dB, the wide stopband with 12~20GHz, and an acceptable return loss.

A Design of the UWB Bandpass Filter with a Good Performance of the Stopband, and Notched Band in Passband (우수한 차단 대역 특성과 통과 대역 내에 저지 대역을 갖는 UWB 대역 통과 필터 설계)

  • An, Jae-Min;Kim, Yu-Seon;Pyo, Hyun-Seong;Lee, Hye-Sun;Lim, Yeong-Seog
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.1
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    • pp.28-35
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    • 2010
  • In this paper, we designed and fabricated a ultra-wideband(UWB) bandpass filter with a good performance of a stopband, and a notched band in passband. The transformed equivalent circuit of the highpass filter was realized by distributed element. A wide-passband with 3-dB fractional bandwidth of more than 100 % was achieved by using optimum response of the HPF. For improving lower and upper stopband characteristic, a cross coupling between feed lines was employed, which was analyzed by desegmentation technique. In order to reject interference of Wireless LAN and Hyper LAN(5.15~5.825 GHz), the narrow notched(rejection) band was realized by a spurline. The fabricated BPF indicated the passband from 3.1 to 10.55 GHz and the flat group delay of less than 0.94 ns over the entire passband except the rejection band. The filter shown sharp attenuation both inside and outside the band and notched band from 5.2 to 6.12 GHz.

A Novel Wideband and Compact Photonic Bandgap Structure using Double-Plane Superposition (양면 중첩기법을 이용하는 새로운 광대역의 소형 포토닉 밴드갭 구조)

  • 김진양;방현국
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2002.11a
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    • pp.413-422
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    • 2002
  • A novel photonic bandgap(PBG) structure is proposed and measured for wide bandgap and compact circuit applications. The proposed structure realizes the ultra-wideband bandgap(2-octave) characteristics by superposing two different PBG structures into a coupled double-plane configuration. A low pass filter fabricated using 3-period of the PBG cells shows 2-octave 10 ㏈ stopband from 4.3 to 16.2 ㎓ and 0.2 ㏈ insertion loss in the passband. Moreover, we confirmed that 44∼70 % size reduction can be achieved using the proposed PBG structures. We expect this novel double-plane PBG structure is widely used for compact and wideband circuit applications, such as compact high-efficiency power amplifiers using harmonic tuning techniques.

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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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