• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.105-110
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• 2007

A tunable band-pass filter of fiber Bragg gratings incorporating the Sagnac loop interferometer configuration is presented. The proposed band-pass filter with extinction ratio 20 dB has practical advantages in terms of price and performance in comparison with the conventional band-pass filter using a circulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1472-1477
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• 2007

Users are offered by the multimedia service of various information on current information-oriented society. The digitize became essential that process of various data is not to selected. Also, Filter technology is required to use the lacking frequency resources efficiently. This paper designs FIR digital band-pass filter of the voice band by narrow band pass filter md verify the characteristics of filter to use by the DSP practice SET.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.899-905
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• 2001

This paper presents a triple-mode dielectric resonator far low loss and simple structure filter design. The BPF(Band Pass Filter) was designed using HFSS simulation results an4 fabricated using proposed resonators. The filter (3-stage BPF) has an insertion loss of about 0.9 dB at the center frequency of 1.93 GHz and a 3 dB bandwidth of about 25 MHz. If more complex characteristic is required, slot coupling between resonators can be used. Especially, the proposed BPF can be applied to the next generation mobile communication IMT-2000 system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.990-995
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• 2000

As the interest in the millimeter wave frequency (30 ~300 GHz) increases, Nonradiative Dielectric (NRD) guide is being more attractive due to its low loss characteristics. Most of millimeter wave components, which can be realized with waveguide, can also be realized with NRD guide since NRD guide has similar dispersion characteristics and field patterns to waveguide. Previously, Variational Method was applied to the gap discontinuity problem to design a gap-coupled NRD bandpass filter. In this paper, the design procedure was simplified by replacing the air gap region with an equivalent circuit model of an evanescent waveguide using the fact that the NRD guide has a similar structure with a dielectric-filled metal waveguide. Prior to applying this design method to the bandpass filter of millimeter wave frequency range, a bandpass filter of which center frequency is 10 GHz(3-Pole, 0.1 dB ripple, 2% fractional bandwidth) was designed and fabricated. The measured result agrees with one simulated with HFSS within an error range of a fabrication.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.142-145
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• 2000

본 논문에서는 C-band용 주파수체배기를 위상잡음 특성이 우수한 SRD를 이용하여 설계, 제작하였다. 1.13GHz의 신호를 체배기에 인가하여 5체배함으로써 5.65GHz대 신호를 얻는 방법을 이용하였다. 또한 원하는 5체배 신호만을 얻기위해서 출력단에 사용되는 대역통과 필터를 기존에 많이 사용되는 Coupled Line 필터 대신에 Microstrip Ring 공진 필터를 사용하는 방식을 이용하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.11-19
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• 1992

This paper proposes a reduced order method which reduces passband error by changing controllability and observability gramian based on weighted functions in the linear time invariant system. In the case that the 4-order model is the reduced to 3-order model in the low-pass filter, the QEI in the proposed method is improved to 6.15724 compared to 10.16464 in the balanced realization method and the sensitivity is improved to 5.45962 compared to 7.790568. The frequency property curves show that the proposed method is superior to the balanced realization method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1663-1668
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• 1993

An X-band contiguous band diplexer is realized by using asymmetrical coupled microstrip lines. The design is based on the singly terminated low pass prototype filter and optimized by using SuperCompack. The designed channel 1 and channel 2 bandwidth is 22%, and 18% respectively, where the center frequency is 9,11 GHz. The measured results of the fabricated diplexer are in good agreement with the designed ones, but the measured insertion loss is slightly highier(0.5dB) than those of the designed value.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.678-684
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• 2013

This paper describes a low-power baseband circuit for SAW-less LTE-Advanced transmitters. The proposed transmitter baseband circuit consists of a 2nd-order Tow-Thomas type active RC-LPF and a 1st-order passive RC LPF. It can provide a 7 multi-channel cut-off frequencies and wide gain control range of -41 dB ~ 0 dB with a 1-dB step. The proposed 2nd-order active RC-LPF adopts an op-amp in which three other sub-op amps are in parallel connected to reduce DC current for different cutoff frequency. In addition, each sub-op amp adopts both Miller and feed-forward phase compensation method to achieve an UGBW of more than 1-GHz with a small DC power consumption. The proposed baseband circuit is implemented in 65-nm CMOS technology, consuming DC power from 6.3 mW to 24.1 mW from a 1.2V supply voltage for each different cut-off frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.648-656
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• 2007

This paper is about band pass filter, using Ceramics in the condition of center frequency 370Hz at milli-wave. The band pass filter is applied to Broadband Convergence Network, representing WLL(Wireless Local Loop) and LMDS(Local Multi-point Distribution Service). Sticking ceramic between strip line on a dielectric material substrate with which conductor's covers upper and basal surface, One will house the exterior by using structural resonance. In this Non Radiative Microstrip Line Filter structure, based upon simulations, generalized the two formulas finding resonant frequency of 1step ceramic resonator and bandwidth of 4step ceramic resonator. Also, As a result of experiment, using Network Analyzer, about created a experiment of structure based on the simulation result of 4-step ceramic resonator, It showed good characteristic of targeted bandwidth, comparing simulated result of 36.58GHz$\sim$37.650GHz with experimented result of 36.6GHz$\sim$37.65GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1292-1296
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• 2002

In this paper, a 3-coupled microstrip line tunable bandpass filter has been designed on the basis of a tonductoriFerroelectricfDielectric (CFD) structure. This tunable filter basically exploits the fact that the increase in the bias voltage leads to the reduction of the effective dielectric constant (eon). This reduced $\varepsilon$eff shifts the center frequency (fc) to the higher value. The characteristics of designed filter are as follows; Return loss (RL) is larger than 10 dB; Insertion loss (IL) is les.i than 3.5 dB: 3-dB bandwidth (BW) is less than 1.18 GHz fc can be tuned from 25.4 GHz to 28.8 GHz over the variation of $\varepsilon$eff, from 10 to 13. Therefore, the tunability comes up to 3.4 GHz. The dimension of the filter designed is 7.0 mm ${\times}$ 5.0 nm ${\times}$ 0.5 mm.