• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1127-1133
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• 2003

In this paper, we proposed a novel folded multi-strip monopole antenna whose height is reduced using folded strip structure. It has a broadband characteristic and its measured impedance bandwidth ratio is approximately 1.85 : 1, from 4.55 GHz to 8.4 GHz, for VSWR$\leq$2. Proposed antenna has vertically polarized omni-directional conical beam radiation pattern. It maintains about the same radiation pattern over entire bandwidth.

• Journal of KIISE:Software and Applications
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• v.26 no.2
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• pp.306-320
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• 1999

본 논문에서는 공간 객체에 대한 다양한 사용자 관점을 제공하기 위하여 객체지향 뷰를 확장한 공간 뷰를 설계 구현한다. 공간 뷰의 기하데이타 차원은 소스 객체의 기하데이타 차원과 다를 수 있으므로 공간 뷰 객체의 기하데이타 표현과 공간연산자가 명시적으로 정의되어야 한다. 그리고 공간 뷰는 대용량의 공간 객체로부터 복잡한 공간 연산에 의해 우도되므로 성능 향상을 위한 실체화 방법이 필요하다. 공간 뷰의 구현 방법은 비-실체화와 실체화 방법이 있다. 그리고 실체화는 값 복사에 의한 실체화와 객체식별자 유지에 의한 실체와 방법으로 나눌 수 있다. 본 논문에서는 비-실체화와 값 복사에 의한 값 복사에 의한 실체화 방법을 구현하고 각각의 질의 처리 방법을 설계 구현한다. 그리고 각 구현 방법의 질의 수행시간을 중점적으로 비교하여 본 논문에서 사용한 공간 뷰의 구현방법을 검증한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.1007-1019
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• 2006

In this paper, the synthesis method of multibeam radiation pattern with multi-directional beams and nulls is proposed. Genetic algorithm is applied for the optimization of amplitude and phase of the feeding signal into each element that is structured in planar array of single patch antenna with an arbitrary field distribution. To verify the validity of the proposed method, $2{\times}2$ planar array antenna is used for the measurement and the measured far field radiation pattern is compared with the simulation result. As a result, the synthesis of multibeam radiation pattern is implemented by the optimization of amplitude and phase of the feeding signal into each element of $8{\times}8$ planar array antenna system.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.2
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• pp.67-78
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• 1994

1996년부터 유럽연합을 중심으로 전자파내성(Electromagnetic immunity; 흔히 군사규격에서는 전자파감응성(electromagnetic susceptibility)이라 함) 규제가 본격적으로 시작될 전망이다. 이러한 전자 파내성 규제는 우리가 과거 '80년대 초에 경험했던 전자파방출(electromagnetic emission; 흔히 electro- magnetic interference 라고도 표현한다) 규제에 비해 규제주파수가 대폭 확장됨(9KHz - 1GHz .rarw. 50/60 Hz - 40 GHz)은 물론, 규제항목도 크게 늘어나기(2개 항목 .rarw. 11개 항목)때문에 본격 규제가 시작되면 우리 산업체에 큰 피해를 초래할 것으로 우려된다. 특히 "복사 전자기장에 대한 전자파내성 요구사항"은 일부 전자파내성 측정항목을 포함하고 있던 안전규 격 등에서도 다루고 있지 않던 것으로서 우리에게는 매우 생소한 항목이다. 이 항목은 과거 미국의 군사 규격등에서 요구했던 항목인데, 앞으로 각국의 상용규격에도 대폭 추가될 것으로 보인다. 이러한 규제는 우리의 생활환경에서 결코 빼놓고 생각할 수 없는, 동시에 가장 큰 전자파장해원인 의도적 복사로서의 방 송신호 및 각종 무선통신 신호에 대해 전기, 전자기기가 전자파내성을 갖고, 성능저하나 오동작을 유발하 지 않아야 함을 요구하는 것이다. 이러한 항목의 평가를 위해서는 대형 시험환경(EMS chamber)과 표준 전자기장 발생장치(signal genera- tors + high power amplifiers), 그리고 오동작 모니터링 장치(monitorring equipments) 등이 필요하기 때 문에 평가시스템 구성에 막대한 비용이 소요된다. 따라서 시스템 구성에 매우 신중을 기해야 하며, 관련 국제표준화규격을 사전에 철저히 이해하여 관련 시험검사를 위한 투자계획을 수립하는 것이 바람직하다. 본 고에서는 복사 전자기장에 대한 대표적인 국제표준화규격을 소개하고, 나아가서 그러한 항목의 평가 시스템의 설계 및 구현에 대해서 설명할 것이다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.957-967
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• 2008

In this paper, we propose the prediction algorithm of radiation emission from the PCB in an enclosure with a rectangular aperture. PCB scanner is used to measure the near field, which is substituted with an equivalent electric dipole source. Green function and Fourier transform are utilized to represent the electromagnetic fields within and outside the enclosure, respectively. The radiation emission is estimated by using the mode matching technique and surface equivalent theorem. The theoretical results are compared with the measurement to check the accuracy of our analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.106-113
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• 2011

In this paper, the non-resonant SWG(Slotted Waveguide) antenna with double slots in narrow wall of rectangular waveguide is designed. Because energy radiated from each slot depends upon inclination angle of slot of the designed antenna, inclination angle of each slot is controlled to satisfy the amplitude distribution for required sidelobe level. Instead of the conventional extraction method of slot conductance, this amplitude distribution is made by the proposed method, which employs far-field radiation pattern calculated by Fourier transform of aperture field distribution on slot. The non-resonant double SWG antenna is designed by the proposed method and is manufactured. The antenna performances are measured and compared with the simulated results.

• Fire Science and Engineering
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• v.25 no.3
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• pp.8-13
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• 2011

The fire compartments which are composed of fire walls and fire doors for buildings are compulsorily required to minimize the fire damage in Korea. The performance standards of fire doors for compartments are regulated by the notification of the ministry of land, transport and maritime affairs and are mainly about the Integrity of the doors not insulation. In this study, we measured the radiant heat of six different kinds of fire doors in fire and analyzed the results and presented the reasons of the need to consider adding the radiant heat standard for fire doors to the notification.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.51-58
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• 2006

The enhancement of antenna near-field measurements is obtained using a general probe compensation equation based on the Lorentz reciprocity theorem and reciprocity notation. The probe compensation is an essential process of the near-field to far-field transformations. Applying the equation proposed in this paper to a planar scanning for a rectangular horn antenna shows that our near-field radiation pattern is similar to that of a far-field and our theory is very simple to use and suitable for most practical applications.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.483-489
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• 2011

In this paper, we propose a new antenna, which has wide bandwidth, good radiation patterns, and high-gain characteristics. We analysis the antenna using FDTD(Finite Difference Time Domain) method. And the antenna parameters are optimized to get maximum bandwidth. From the measured results, the bandwidth of the antenna is 0.839 octave, for the S11${\leq}$-10 dB. And the measured cross polarization level of the proposed antenna is less than -25 dB at the center frequency. Experimental data of the return loss and the radiation pattern of the proposed antenna are also presented, and the experimental bandwidth characteristics are relatively in good agreement with the FDTD results. The proposed antenna can be applied to MIMO, LAN, biomedical instruments, broadcasting-network system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.234-241
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• 2000

During the EFT immunity test, the fast transient voltage is injected to the power or signal line. The radiated noise from these lines influences the near-by EUT, and consequently, the reliability of the test result can be jeopardized. The measured data of the field strength and wave shape of the noise were compared with the result of the mathematical analysis using transmission line model. When the tests were performed by the conditions the same as stated in IEC 61000-4-4, the results showed that the magnitude of the radiated electric field strength was about 2.4KV/m, and it can cause severe interference to the intended operation of EUT.