• Title/Summary/Keyword: Bandstop Filter

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Compact Tunable Bandstop Filter Using DOS Section (DGS 구조를 이용한 소형 가변 대역 억제 필터)

  • Sung, Young-Je
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.12
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    • pp.1333-1338
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    • 2008
  • In this paper, RF varactor diode are applied to the design of miniaturized and tunable bandstop filter. The proposed bandstop filter is based on a Defected Ground Structure(DGS) section topology. The designed tunable bandstop filter can achieve a significant size reduction by with loading capacitance component of varactor diode. It is observed from the measured results that the proposed tunable bandstop filter shows a wide tuning range of 42.9 % from 1.01 GHz to 1.99 GHz. The rejection level in the stopband is higher as the number of DGS section increases. In case of the proposed tunable bandstop filter with two DGS sections, the rejection level of the filter is better than 20 dB in the stopband during the tuning. In this case, the maximum insertion loss in the lower passband is 0.5 dB.

Tunable Bandstop Filter with Combined Right/Left-Handed Transmission Lines (Right/Left-Handed 전송 선로를 결합한 가변 대역 저지 필터)

  • Sung, Gyu-Je;Kim, Ell-Kou;Kim, Young;Yoon, Young-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.10
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    • pp.1122-1128
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    • 2008
  • A novel tunable bandstop filter was proposed. It is composed of a right-handed transmission line, which has lowpass characteristics, and a left-handed transmission line which has highpass characteristics. Dispersion relations for the unit cells of RHTL and LHTL were derived by the method of ABCD parameter analysis. Varactor diodes and chip inductors were used to make the unit cells of RHTL and LHTL. A tunable bandstop filter was designed and fabricated by the parallel connection of RHTL and LHTL. The measured results of the proposed tunable bandstop filter are agreed well with the simulated results.

A Design of Novel Compact Microstrip Bandstop Filters Based on Split-Ring Resonators and Spiral Resonators (Split-Ring 공진기와 Spiral 공진기를 이용한 새로운 소형의 마이크로스트립 대역 저지 필터 설계)

  • Lee, Jong-Hyuk;Oh, Young-Chul;Myung, Noh-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.7
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    • pp.796-808
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    • 2007
  • In this paper, two novel compact microstrip bandstop filters using complimentary split ring resonators(CSRRs) and spiral resonators is proposed. The first one is the bandstop filter using an array of CSRRs etched on the center line of a microstrip. The bandstop is due to the presence of negative effective permittivity and positive permeability near resonant frequency which prevent the wave propagation. The second on is the bandstop filter using an array of spiral resonators etched on the center line of a microstrip. The bandstop is due to the self-resonance of spiral circuit. We have achieved controllable resonance frequency and bandwidth, super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff. The electrical sizes of two proposed filter are very small. Additionally, they can be easily fabricated and compatible with MMIC or PCB technology.

Dielectric Waveguide Channel Dropping Filter (유전체 도파관을 이용한 채널 드로핑 필터)

  • 김신기;박동철;오승엽
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.1
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    • pp.1-7
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    • 1988
  • A new type broadband channel dropping filter which has a potential use as a millimeter-wave multiplexer has been realized by properly connecting 3-dB directional couplers and bandstop filters. 90\ulcorner3-dB directional couplers have been designed using two nonuniformly coupled dielectric image guides, while bandstop filters with Chebyshev passbands have been designed using dielectric image-guide grating structure. Effective dielectric constant method has been aplied to the image-guide dispersion analysis and to the design of bandstop gratings and 3-dB couplers. Experimental results in excellent agreement with computed responses are demonstrated.

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Design of a Compact Lowpass Filter having Wide Bandstop Characteristics for Microwave and Millimeter-Wave Circuit Applications (마이크로파 및 밀리미터파 회로 응용을 위한 넓은 저지대역 특성을 지닌 소형의 저역 통과 여파기 설계)

  • 서재옥;박성대;김진양;강남기;이해영
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.3
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    • pp.283-289
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    • 2003
  • In this paper, we proposed novel multilayer photonic bandgap(PBG) structure using DSL(Descended Signal Line). From measurement result, the proposed PBG structure using DSL is reduced 72 % at size and increased 13 % at bandwidth compared to typical multilayer DGS(Defected Ground Structure). It is also reduced 42 % at size and increased 23 % at bandwidth compared to PBG structure using EGP(Elevated Ground Plane). In case of measurement for manufactured six PBG patterns, all patterns have the same cutoff frequency and bandstop characteristics. So it can be used for bandstop filter having very precise tolerance of below 300 MHz at 20 ㎓ if it is applied to real product and this filter will be useful for small microwave integrated circuit and module development.

Miniaturized Bandstop Filter Using Meander Spurline and Capacitively Loaded Stubs

  • Liu, Haiwen;Knoechel, Reinhard H.;Schuenemann, Klaus F.
    • ETRI Journal
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    • v.29 no.5
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    • pp.614-618
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    • 2007
  • A miniaturized bandstop filter (BSF) is introduced in this paper. The filter consists of one meander spurline and a pair of capacitively loaded stubs. The meander spurline with low resonant frequency and improved slow-wave factor exhibits excellent resonant bandgap characteristics which can be modeled by a longitudinally coupled resonator. The design of the proposed microstrip BSF is presented, and its performance is measured. Measurements show that there is a stopband from 2.3 to 5.6 GHz with $S_{21}$ less than -20 dB. The total length of this BSF equals 23 mm.

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Design of a Compact Bandstop Filter-combined UHF-band CRLH Bandpass Filter to Suppress the Spurious in L-band (L대역 불요파 저감을 위한, UHF대역 CRLH 대역통과 여파기와 소형 대역저지 여파기의 결합 설계)

  • Eom, Da-Jeong;Kahng, Sung-Tek;Mok, Se-Gyoon;Song, Choong-Ho;Woo, Chun-Sik;Park, Do-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.104-109
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    • 2012
  • In this paper, we propose a way to improve the quality of L-band wireless communication from unfriendly influential factors lying in the neighboring RF bands. The UHF-band system has resonator components and they generate harmonics as the spurious in the L-band. Therefore, a metamaterial CRLH bandpass filter is designed for the purpose of system miniaturization and smaller insertion loss, and its spurious phenomenon is observed in the frequency domain. And its harmonics in the L-band are suppressed by a compact bandstop filter whose equivalent circuit is newly developed. The design methodology is validated by the equivalent circuit to be compared with commercial full-wave EM software simulations, where the spurious is dropped by 20dB. Also, the advantage of the proposed design is presented by the comparison where our filter is much smaller than the conventional parallel edge coupled filter by over 50%, with excellent harmonic suppression.

Compact Planar Dual-Wideband Bandstop Filters with Cross Coupling and Open-Ended Stepped Impedance Resonators

  • Velidi, Vamsi Krishna;Sanyal, Subrata
    • ETRI Journal
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    • v.32 no.1
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    • pp.148-150
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    • 2010
  • This letter presents the design of a compact bandstop filter (BSF) operating at two frequencies. The proposed BSF consists of open-ended stepped impedance resonators (OSIR) and an end-shorted parallel-coupled microstrip line (E-PCML). The OSIRs are used to achieve the impedance-controlled stopband positions. The wide BSF bandwidths are achieved through enhanced coupling of the E-PCML. Explicit design guidelines are derived using a lossless transmission line model. To validate theoretical predictions, a prototype dual-band BSF operating at 900 MHz and 2,100 MHz with fractional bandwidths of 72% and 36%, respectively, is implemented in microstrip.

Micromachined overlapped resonators for wide electromagnetic coupling ranges (광대역 전자기 커플링 용 미세 가공 중첩 공진기)

  • Liamas-Garro, Ignacio;Kim, Jung-Mu;Kim, Yong-Kweon
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2389-2391
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    • 2005
  • In this paper, a compact S type resonator is presented, where the proposed resonator is surface micromachined over transmission lines or other resonators, in order to obtain a wide range of possible electromagnetic couplings. The structure has been applied in two compact, bandstop and bandpass filters with moderate fractional bandwidths (FBW) of 20% and 25% respectively. The bandstop filter presented, was designed by the combination of two design methods in order to obtain the proposed fractional bandwidth, where traditionally, coupled resonator bandstop filters have been used for narrow stopbands. The bandpass filter illustrates the use of the proposed suspended resonator structure to obtain a wide range of electric type coupling coefficients, and external quality factors for the filter. This paper describes the design methodology, concepts and fabrication method proposed for the design of these filters.

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Wideband Bandstop Filter Based on Capacitively Coupled λ/4 Short-Circuited Lines

  • Duong, Thai Hoa;Kim, Ihn-Seok
    • Journal of electromagnetic engineering and science
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    • v.10 no.3
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    • pp.92-98
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    • 2010
  • A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled $\lambda/4$ short-circuited lines with opposite ground positions, while the second is a capacitively coupled $\lambda/4$ short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 dB rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 GHz. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 GHz) band-pass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is $3{\times}6.3\times0.45\;mm^3$.