• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.106-109
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• 2017

저궤도 위성의 배터리는 일반적으로 임무 및 식 구간에서의 부족한 전력 공급을 위해서 사용 되며, 버스 전압에 연결되어 있는 경우 출력 필터의 일부 기능을 담당하게 된다. 따라서 배터리의 주요 설계 요인은 전력 요구 분석을 통해 에너지 균형조건을 맞추기 위한 설계가 일반적이고, 배터리를 이용한 출력 전력 필터의 역할은 설계의 요인에 포함 되지 않는다. 하지만, 배터리는 전력 공급의 역할이외에도, 출력 전류의 변동이 극심하거나, 주기적으로 일정한 출력 변동을 발생하는 로드 등에 대한 필터 역할로써도 사용이 가능하다. 출력 커패시터를 배터리로 대체 할 경우 inrush 전류의 감소 및 추가적인 보호회로의 설계의 불필요 등의 장점을 가지고 있다. 배터리를 위성의 전력 공급을 위한 목적으로 사용하는 경우에는 전력 요구 분석을 통한 설계가 타당하나, 출력 로드 변동에 따른 영향을 줄이기 위해 필터로써 배터리를 사용하는 경우에는 사이즈 및 임피던스에 대한 추가적인 분석이 요구 된다. 따라서 본 논문에서는 저궤도 위성에서의 출력 전력 필터로 배터리를 이용한 설계 방안 및 성능 분석을 수행 하였다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.35-36
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• 2014

본 논문은 Rear Combination LED Lamp 동작 시 전류와 광출력의 변동폭를 최소화하는 LED 조명광원의 특성을 고려하여 정전류 회로의 구현이 유리한 DC/DC 컨버터의 EMC 고효율 필터를 제안하여 외부의 전자계로부터 장애를 유발하지 않고, 일정 수준의 전자파 환경에서도 오동작 없이 원할하게 작동될 수 있도록 관련 기기 상호간의 전파 환경을 개선하는 고효율 Filter를 제안 하고자 한다. 본 논문에서 제안한 Filter는 EMI 측정을 통해 타당성과 우수성을 검증하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.143-148
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• 2022

For the purpose of treating health checkups and recovery of patients in a super-aged society, hospitals use devices designed with a reduction circuit of electromagnetic waves associated with the specific absorption rate of electromagnetic waves absorbed by the human body. In this paper, we proposed a filter improvement design method capable of reducing electromagnetic waves. As a result of confirming the validity of the proposed technique through simulation and experimental results, the following result values were obtained. Applying the common-mode (CM) inductor 4 mH to a calibration circuit, noise decreased in a multiband spectrum. Using the differential mode(DM) inductor 40 µH element in the primary calibration circuit, the noise decreased by 15 dB or more in the 3 MHz band spectrum. Also, applying the Admittance Capacitance (Y-Cap) 10 nF element in the secondary calibration circuit resulted in the decrease by more than 30 dB in the band spectrum before 2 MHz. After using a common-mode inductor 4 mH element in the tertiary calibration circuit, it decreased by more than 15 dB in the band spectrum after 2 MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.240-243
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• 2001

As electronic industry and radio communication technologies progress, mankind enjoys its abundant life. On the other hand, it becomes possible that the electrical and electronic equipments are on light weight, small size, high speed, broad bandwidth, and operation by small energy. At the same time, many social problems like EMI/EMS by electromagnetic waves occur. Therefore, tile organizations such as CISPR, FCC, ANCI, etc., have provided the standards of electromagnetic wave environments for the countermeasure of the EMC. In this paper, we designed and studied a new EMI filter for multi-tap in the frequency band from 150 kHz to 30 MHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.235-240
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• 2020

This study evaluated the improvements for circuits of a combat vehicle distribution box to reduce the noise generated in electromagnetic compatibility (EMC) testing. An analysis of the distribution boxes that failed the standard revealed the conducted noise generated from the converter and semiconductor switching elements on the circuit board. The distribution box transfers power from the generator and battery to the cooling system of a combat vehicle to keep turning the air conditioner on and off. Two methods were proposed to overcome this problem: a passive filter was added to the circuit board for the first method, and the converter and switching elements were replaced with the relays for the second method. Both methods were effective in reducing noise, but a greater improvement was obtained from the second method. The second method was applied to a combat vehicle system and was found to be suitable according to the EMC standards.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.393-400
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• 2003

This paper deals with the design and manufacturing technique of EQM(Engineering Qualification Model) of input multiplexer(IMUX) for the Ku-band satellite transponder. Channel dropping method by circulator chain structure is adopted for demultiplexing each channel. External equalizers are attached behind channel filters fur reduction of group delay variation and amplitude variation simultaneously. Both channel filters and equalizers adopted dual-mode technique in design f3r mass and volume reduction. Channel filters are designed to have 8-pole elliptic response and equalizers to be of 2-pole reflection type. For good temperature stability characteristics, INVAR36 material is used for channel filters and external equalizers. Vibration test, Thermal Vacuum Test, and EMC test have been performed on input multiplexer and it is shown to be suitable for Ku-band satellite transponder.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.636-645
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• 2015

In this paper, unusual harmonics noise problem of digital electronic products in mass production was introduced and a practical solution was proposed. Generally, 5th or higher harmonics noise level has been ignored in circuit designs because over 5th harmonics noise decreases by 40 (dB/decade). Through some measurements, it is confirmed that over 10th harmonics noise can propagate and radiate in case of a certain PCB or housing conditions. We propose a capacitively loaded micro-strip low pass filter for commercial products having spatial design constraints and measured the effectiveness. The proposed structure can solve both of the continual increment of harmonics noise level and the spatial design constraint of commercial products. We expect the proposed method be effectively used for various digital electronic products.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.2
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• pp.222-231
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• 2011

In this paper, we have proposed a method which can make it possible to stably transmit and receive data like the ARC-164 radio frequency hopping environment as a S/W packet modem with PSK modulation. This is a method that the S/W packet modem with PSK digital modulation and the use of PC sound cards change over from data to voice signals and then transmit/receive data. We confirmed not only that it is possible to solve the slow speed communication with the use of sending data through multi-channels and PSK modulation that has the ability to methodically improve transmission rates, but also that it is possible to send the state of frequency hopping stably. In conclusion, we've confirmed both tactical values that though the transmission rate may be a tad slow, a state of frequency hopping of more than 94% confidence plus voice and data can be sent via radio at the same time. In this paper, the proposed S/W packet modem is only an implemented S/W component, so when we apply it to aircraft that we don't consider EMC problems with, then we have the advantage of a wider use of conventional UHF/VHF/HF radio that is possible to voice communication. If we recognize these operational requirements, we can apply for a lot of field equipment efficiently.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.210-210
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• 2020

LID (Low Impact Development, 저영향개발)는 산업화 및 도시화 진행 지역에서 비점오염원으로부터 배출되는 오염물질을 제어해 개발지역 내 자연순화 기능을 최대한 유지하고, 물순환 기능증대를 통해 강우 유출수를 지역 내에서 관리하는 것을 목표로 한다. 비점오염원 저감 LID 시설에는 자연형과 장치형 시설이 있다. 자연형 시설에는 저류형, 침투, 식생형 시설 등이 있다. 특히, 침투시설에는 대표적으로 투수블럭이 있으며, 이는 투수성 포장재를 통해 강우 유출수를 지하로 침투시켜 여과나 흡착 등으로 비점오염물질을 제어하는 시설이다. 장치형 시설로는 여과재나 망을 이용해 비점오염물질을 분리하는 여과형 및 스크린형 시설, 응집과 침전을 통해 비점오염물질을 분리하는 응집·침전 시설 등이 있다. 이에 본 연구는 2016년부터 2018년 3년간 전주 서곡지구 지역 내 설치된 필터형 투수블럭, 틈새형 투수블럭에서 진행했다. 각각의 투수블럭에서 총 19회, 20회의 강우 모니터링을 실시했고, 오염물질 유입 및 유출 EMC 등의 분석을 통해 유출 및 오염물질 저감효과를 분석했다. 연구 대상 각 투수블럭의 주요 제원은 시설 용량 14.4㎥, 시설 면적은 14.4㎡이다. 모니터링 결과값을 분석한 결과 필터형 투수블럭의 경우 유출 저감율은 17.4 ~ 100%, 틈새형 투수블럭은 29.6 ~ 100%이었다. 필터형 투수블럭과 틈새형 투수블럭의 단위면적당 유량 저감량은 각각 0.014 ~ 0.583㎥/㎡, 0.035 ~ 0.588㎥/㎡이었다. 오염물질 저감효율을 분석한 결과 유기물 항목(BOD, TOC)의 경우 틈새형 투수블럭에서의 저감효율(BOD 93.59%, TOC 90.39%)이 필터형 투수블럭에서의 저감효율(BOD 89.99%, TOC 86.94%) 보다 다소 높게 나타났다. 영양염류 항목(T-N, T-P)의 경우 필터형, 틈새형 모두 비슷한 저감효율(필터형 T-N 89.02%, 필터형 T-P 98.12%, 틈새형 T-N 90.41%, 틈새형 T-P 98.04%)을 보였다.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.535-541
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• 2013

The urbanization affects significantly on a natural water circulation system by increasing the imperviousness rate. It is also negatively affecting on urban temperature, environmental pollution, water quality, and aqua-ecosystems. The Korea MOE (Ministry of Environment) adapted a new environmental policy in order to reduce the impact of urbanization, which is the Green Stormwater Infrastructure (GSI) program. The GSI can be achieved by protecting conservable green spaces, enlarging more green spaces, and constructing more permeable pavements. The GSI is including many different techniques such as bioretention, rain garden, infiltration trench and so on. Also It is the infrastructures using natural mechanisms of soils, microorganisms, plants and animals on a water circulation system and pollutant reduction. In this research, a multi functional GSI technology with infiltration-filtration mechanisms has been developed and performed lab-scale tests to evaluate the performances about infiltration rate restoration and pollutant reduction. The most of pollutants including metals, organics and particulates were reduced about 50~90% due to water infiltration and storage functions. The clogging was found when the TSS loading rate was reached on $8.3{\sim}9.0kg/m^2$, which value is higher than the values in literatures. It means the new technology can show high performances with low maintenances.