• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.169-172
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• 2002

In this paper, the design formulas for bandpass filters using parallel coupled stepped impedance resonators(SIR) are derived. General content about basic feature of stepped impedance resonators(SIR) is represented. The filters and duplexer using stepped impedance resonators(SIR) have been designed and realized with the presented design method at IMT-2000 frequency band Simulations have used serenade circuit simulation and HFSS EM-simulation. We were showed excellent agreements between SIR design theory and simulation results on the multi-layer filter/duplexer.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.91-96
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• 2011

In this paper, we propose a microstrip bandpass filter using stepped-impedance coupled-line hairpin resonators. The stepped-impedance coupled-line hairpin resonator has extended harmonic suppression in comparison with a conventional hairpin resonator due to transmission zero and the movement of harmonic frequencies resulting from the stepped-impedance characteristic. A high-pass type impedance/admittance inverter is employed in order to improve the lower frequency skirt characteristics of the passband. A 4-pole bandpass filter is designed and fabricated at 1.8 GHz. The measured results show the excellent attenuation performance at the stopband which is greater than 30 dB up to 10 GHz.

• Journal of electromagnetic engineering and science
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• 제18권2호
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• pp.73-77
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• 2018

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz.

• ETRI Journal
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• 제32권1호
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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.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.43-46
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• 2011

A novel circuit structure of dual-band bandstop filters is proposed in this paper. This structure comprises two shunt-connected tri-section stepped impedance resonators with a transmission line in between. Theoretical analysis from the equivalent circuit and design procedures are described. We represented graphs for filter design from the derived synthesis equations by resonance condition of circuits. Notably, advantages of the proposed filter structure are compact size in design, wide range of realizable resonance frequency ratio, and more realizable impedances.

• Journal of electromagnetic engineering and science
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• 제7권4호
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• pp.190-194
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• 2007

In this paper, a cross-coupled microstrip combline bandpass filter using stepped-impedance resonators(SIRs) is proposed. In order to improve the selectivity as well as the insertion loss, the SIR configuration is used. The cross coupling is also introduced to enhance the selectivity. The improvement of the insertion loss is demonstrated not only by deriving the quality factor of the SIR but through the measured performances. Both the proposed and the conventional combline bandpass filter with 5 % of fractional bandwidth at 2 GHz were fabricated and tested. Compared to the conventional combline bandpass filter, the proposed one exhibits the improved selectivity as well as the lower insertion loss characteristics.

• Journal of electromagnetic engineering and science
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• 제8권4호
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• pp.144-147
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• 2008

This paper proposes a tunable combline bandpass filter with high selectivity, constant bandwidth, and good stopband performances. A filter with these characteristics is obtained by applying cross-coupling to the conventional combline bandpass filter using stepped-impedance resonators(SIRs). For high selectivity and constant bandwidth, cross-coupling is utilized and the SIR configuration is used for enhanced stopband performances. The proposed combline tunable bandpass filter with 5% of fractional bandwidth at 1.6 GHz was fabricated and tested. The measured results showed 11.6% tunability with constant bandwidth, high selectivity and enhanced stopband characteristics.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권1호
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• pp.65-72
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• 2011

In this paper, the T-shape stepped impedance resonators are adopted for the design of microstrip bandpass filters for wide harmonics suppression. The proposed filters are operated at the center frequency of 2.44 GHz and 5.20 GHz, respectively. These bandpass filters have been also applied for a high performance diplexer. The insertion losses at the center frequencies of 2.44 and 5.20 GHz are 1.23 and 1.18, respectively. The applicable return losses for both frequency bands and a wide stopband better than 17 dB up to 20 GHz have been obtained.

• 한국항행학회논문지
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• 제27권1호
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• pp.57-62
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• 2023

본 논문은 이중 모드 SIR(stepped-impedance resonator)과 평행 결합선로를 이용한 3중-대역 대역통과 필터를 제안한다. 제안된 필터는 단락 종단을 갖는 inter-digital 및 comb-line 형태의 평행 결합선로와 개방형 스터브를 갖는 U-자형 SIR로 구성되었다. 개방형 스터브가 있는 2개의 U-자형 SIR은 첫 번째와 세 번째 통과 대역을 만들고, 중앙의 평행 결합선로 공진기는 두 번째 통과 대역을 만든다. 5개의 공진기와 평행 결합선로 구조의 우/기모드 입력 임피던스를 해석하여 3중-대역 대역통과 필터의 산란 파라미터를 유도하였다. 유도된 산란 파라미터를 이용하여 새로운 3중-대역 대역통과 필터를 설계하고 제작하였다. 제작된 필터는 0.2×0.19 λ_g²의 작은 크기를 가지며, 측정 결과는 높은 대역 격리도를 보여 주고 있다.

• 한국정보통신학회논문지
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• 제15권8호
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• pp.1653-1658
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• 2011

본 논문에서는 듀얼 밴드 대역저지 필터의 소형화 설계를 위한 새로운 구조를 제안한다. 본 구조는 전송 라인과 두 개의 병렬로 연결된 3단 계단형 임피던스 공진기로 구성되어 있다. 필터의 등가회로를 통한 이론적 분석과 설계 절차를 나타내었다. 공진조건으로부터 유도한 방정식으로부터 각 설계 변수에 대한 특성 결과를 그래프로 나타내어 설계의 편의성을 제공한다. 제안된 필터 구조의 장점은 설계의 소형화 가능성, 구현 가능한 공진 주파수의 비율이 넓은 점, 그리고 구현 가능한 임피던스의 선택이 자유롭다는 점이다.