• 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.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.17-22
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• 2005

This paper presents a improvement equivalent circuit model for Miniaturized LTCC bandpass filter with two transmission zeros using feed-back capacitor. The bandpass filter equivalent circuit is evaluated by parallel network analysis. Besides, the filter is modeled by proposed passive element modeling algorithm in previous work. Compared to the equivalent circuit of established paper that is configured by excepted capacitance between ground plate and signal plate, this model can include that. The result, the LTCC bandpass filter reduce layers and the size is more smaller.

• Journal of electromagnetic engineering and science
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• 제8권1호
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• pp.12-16
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• 2008

In this paper, we introduce a coupling, which is achieved through the aperture instead of the conventional edge coupling, so that the bandpass filter is reduced less than half in size compared to conventional planar type. The resulting filter configuration has a near two-fold symmetry, where the aperture coupling is used in the middle of the coupling stages. We designed a bandpass filter using two tapped hairpin resonators, of which the order becomes four. The designed bandpass filter has the size of $8.9{\times}18.3\;mm$. It has the return loss better than 17dB and the insertion loss of less than 5 dB in overall passband. The measured results show good agreements with simulated ones.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권6호
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• pp.268-271
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• 2004

An analytic design formula is proposed for a TEM mode dielectric bandpass filter with attenuation poles at desired frequencies in the stop band. In order to sustain the constant ripple in the passband due to attenuation poles, the initial resonant frequencies of the various resonators adopted in a filter with attenuation poles are newly calculated. The proposed design theory is verified by designing various bandpass filters with attenuation poles in the stop band.

• Journal of electromagnetic engineering and science
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• 제5권2호
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• pp.80-86
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• 2005

In this paper, a novel varactor-tuned combline bandpass filter is presented. The coupling varactor diode between line elements is introduced to control the passband bandwidth so that the passband bandwidth can be maintained almost constant within the tuning range. The equivalent circuit and design equations are derived, and the optimum design is discussed. A 1.7 GHz, two-pole bandpass filter with a bandwidth of $4.5\%$ was constructed. The absolute passband bandwidth was maintained almost constant within more than 0.4 octave tuning range.

• Journal of information and communication convergence engineering
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• 제8권5호
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• pp.484-488
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• 2010

In this paper, we present a novel tunable microstrip bandpass filter based on split ring resonators (SRRs). The varactors are reverse-biased semiconductor diode, and are connected between the concentric rings of the SRR. An individual varactor loaded SRR based bandpass tunable filter module is analyzed. Then a second order tunable filter with 7% fractional bandwidth and a tuning range from 2.75 to 2.86 GHz is assembled from basic filter modules. The simulator HFSS (V10) is used to design the tunable filter and to simulate. The results show good characteristics is created.

• 한국위성정보통신학회논문지
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• 제11권4호
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• pp.44-47
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• 2016

TVWS에 대한 관심이 증가하고 있고, TVWS를 이용하는 통신시스템과 서비스에 대한 연구가 활발히 진행되고 있다. TVWS는 사용할 수 있는 주파수가 지역적으로 그리고 시간적으로 다르다. 때문에 TVWS를 이용하는 RF 시스템이 주파수가변 대역통과필터를 사용하면 시스템을 효과적으로 운용할 수 있다. 본 논문에서는 470 ~ 698MHz에서 동작하는 주파수가변 대역통과필터를 설계 및 구현하였다. 그리고 주파수가변 대역통과필터는 제어의 용이성과 크기를 고려해서 2-pole로 설계하였다. 구현한 주파수가변 대역통과필터는 제어전압을 1.58 ~ 3.93V 가변하면 470 ~ 698MHz에서 동작하며, 삽입손실은 최대 4.78dB, 반사손실은 10dB 이하를 갖는 것으로 측정되었다. 본 논문의 주파수가변 대역통과필터는 TVWS에서 동작하는 수신기에 직접 사용이 가능하며, 본 논문에서 사용한 주파수가변 대역통과필터의 설계 절차는 대전력 주파수가변 대역통과필터의 개발을 위한 기초 자료로 활용될 수 있다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.39-43
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• 2002

In this thesis, a λ/4 hair-pin resonator is proposed to reduce the size of resonators. A LTCC MLC bandpass filter is designed using the λ/4 hair-pin resonators. The electromagnetic coupling structure between two planar resonators is analysed. The equivalent circuit is derived to explain the behavior of the LTCC MLC bandpass filter using λ/4 hair-pin resonators. A design procedure is also described. The simulated and measured results of 2-pole bandpass filter are presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.795-798
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• 1998

In this paper, a new class of bandpass filter using a modified Chebyshev lowpass filter function is described. The prosposed bandpass filter which exhibits diminishing ripples in the passband has maximum value at the center frequency. Due to the lower pole-Q, the performance in the frequency and time domains is improved as compared with the classical Chebyshev bandpass filter.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.188-192
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• 2003

A multilayer two-stage LC bandpass filter using low-temperature cofired-ceramic (LTCC) is proposed in this paper. The proposed bandpass filter is composed of two ceramic substrates with different dielectric constant instead of single ceramic material from top to bottom layer. The bandpass filter size is $2.0 mm{\times}1.2 mm{\times}0.8 mm$. Positioning of attenuation polefrequency, importance parameter for a performance of filter, is discussed using even-odd mode analysis by tuned capacitance of coupling capacitor and those results is implemented to LTCC filter circuit. Measured filter performances show that the insertion losses are -4.5dB, -4.1dB at 2.45GHz, 2.75GHz and the return losses are -8.5dB, 8.7dB.