• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1086-1096
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• 2011

In this paper, we present the trisection band-pass filter with a transmission zero at 2.63 GHz, which has a center frequency of 2.44 GHz, relative bandwidth of 5 %, and return loss of 18 dB, based on a multi-port ElectroMagnetic simulation. The coupling matrix for the trisection filter is calculated and this filter is transformed into band-pass filter prototype through a lossless 2-port circuit transformation. The J-inverter values and slope parameters of each individual resonator are computed using an EM simulation Y-parameters of the filter with multi port. The dimensions of desired filter are determined by matching the computed J-inverter and susceptance slope parameters to those of the prototype band-pass filter. Undesired cross-couplings are found to occur which does not appear in the prototype trisection filter. To overcome the problem of undesired couplings, the filter was optimized to satisfy the same frequency response of prototype filter. The validity of the proposed design method was verified through the implementation of the designed and optimized filter.

• The Journal of the Acoustical Society of Korea
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• v.5 no.3
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• pp.44-49
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• 1986

회로의 간편성에 최대 역점을 두어 PLL을 이용한 정현파 간섭음을 실시간으로 제거하는 방식을 제안하였다. SC 여파기를 이용한 적응 노치 여파기ㅘ 적응 대역 여파기를 자기 동조법으로 구동시킴으 로써 간섭음을 제거하였다. SC 여파기의 구동 스위칭 주파수는 제거하려는 신호 주파수으 L49배가 되 도록 하엿으며 소자의 동작 특성상 4KHz의 간섭음 제거 대역을 갖게 된다. 노치 여파기는 6차 여파기 이고 감쇄도는 중심 주파수에서 약 -56dB이다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.4
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• pp.42-47
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• 1999

Based on characteristics of resonator in BPF, a resonant characteristic is obtained by using variation of characteristic impedance in rectangular waveguide. And we have designed and made a novel waveguide BPF with this phenomenon. This filter can be made with arbitrary lengths of rectangular waveguide resonators.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.4
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• pp.155-158
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• 1985

A simple active-R filter is proposed by utilizing only four resistors and two operational amplifiers. This filter has multi-functional characteristics and decreases the ratio of resistors. The sensitivity of $W_r$ and $Q_r$ as the parameter of filter is very low and the operating frequency of this active-R filter is possible in the high frequency. The integration of this active-R filter is easy due to the decrease in the number of resistors and the lowering of the ration of resistors. The experiment shows that all the characteristics of this active-R filter are in accordance with thory.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.309-312
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• 2003

본 논문에서는 유전체 기판형태에서 대역통과 여파기의 크기를 줄이며, 감쇄극을 통과대역 양쪽에 적절하게 위치시키어 감쇄특성을 개선시킬 수 있는 구조를 제안한다. 제시된 구조는 일반적인 헤어핀구조와 접지면에 슬롯라인을 구현해주어 2단 대역통과 여파기를 설계하였다. 설계된 대역 여파기의 등가회로를 제시하였고 시뮬레이션 및 측정 결과를 비교하였다. 구현된 여파기는 일반적인 결합선로 여파기에 비해 크기를 크게 줄 일수 있었고, 감쇄특성은 3단 대역통과 여파기의 감쇄특성에 비교할 수 있다. 제시된 구조는 소형화 및 성능개선에 장점을 가지고 있어 다른 소자에도 많은 적용이 가능할 것으로 생각된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.620-625
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• 2003

The coplanar waveguide bandpass filter using folded-line stepped-impedance resonators(SIRs) is proposed. The folded-line SIR has about λ/8 length using the short-circuited end on coplanar waveguide. It make that the bandpass filter has the half size in comparison with general λ/4 SIR filter. In this paper, we derive the equivalent circuit and design the bandpass filter by using that. We design and fabricate the bandpass filter which has 5 GHz center frequency and 3 % fractional bandwidth. The measurement results fur 4-pole folded SIR bandpass filter agreed well with full-wave simulation and equivalent circuit results. The fabricated bandpass filter has a good spurious characteristic, which the harmonic frequency appeared at 2.5f$\_$0/). The proposed folded-line SIR bandpass filter are applicable for MMIC and High-Tc superconducting filters. bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.20-26
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• 2003

This paper presents hairpin-comb bandpass filter using ground aperture. Hairpin-comb resonator maintains the weak coupling though the space between two resonators is very small. This has the good merit that the entire filter size is small for narrowband bandpass filter. The coupling between two hairpin-comb resonators so very weak that can't be applicable to general microstrip. We compensate the coupling by using ground aperture. It makes the hairpin-comb filter possible that can be applicable to general microstrip. Also it has the good merit which adjusts the bandwidth by changing the size of aperture without changing the space. In this paper, we fabricate the bandpass filter, which has 1.78 GHz center frequency and 62 MHz (3.5%) fractional bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.554-559
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• 2004

A novel miniaturized 2-pole band pass filter(BPF) is proposed and it has an overlapped hairpin and slot structure on the upper and bottom plane of microstrip lines. Due to the overlapped structure of a hairpin and a slot, the size of the proposed BPF is quite smaller than that of a general BPF having coupled lines. The size of the proposed BPF is reduced to 33 % comparing with the conventional λ/4 coupled BPF. The attenuation is improved by controlling the attenuation poles properly using the proposed structure. The proposed 2-pole BPF is fabricated with a narrow bandwidth(69 ㎒) at center frequency, 1.9 ㎓ which is difficult to make that narrow bandwidth in the conventional coupled lines due to impractical spacing. The design method in this paper can be applied to the design of other microwave circuits to reduce the size and improve the performances.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.31-37
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• 2008

In order to organize the Intelligent Transport System(ITS) as a communication equipment, the satellite and wireless system demand broadband characteristics for collecting information from the wide road. Band-pass filters (BPF) or broad BPFs used in such communication system are required for broadband characteristics. This paper presents a design of such broad BPF which can be used in the system. Designed BPF which was difficult to get broadband characteristics after realization, become possible to realize filter with broad bandwidth and compact structure using parallel coupled line. The designed filter achieved the insertion losses improved by 0.4 dB and the return losses improved by 17.4 dB respectively with 60% of bandwidth at the 5.8 GHz of the center frequency, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1502-1507
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• 2005

The SA filters have a very flexible structure by limiting the maximum subwindow size. This flexible structure presents an effective trade-off between the complexity and performance of the filters. In this paper, experimental results showing the performance variation according to the change of filter order and subfilter type(such as max, min, exclusive-OR, mod) are presented. We designed optimal SA filters minimizing MSE for the various noise conditions. These results show several new properties of SA filters.