• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.135-138
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• 2000

This paper presents design for radiation element of slotted waveguide by the method of moment. The piecewise sinusoidal function as the basis function is used for the Moment Method. From the analytically results based on the Galerkin's moment method, frequency characteristics and radiation power is investigated for the design parameter such as the slot length, offset and angle. This paper also discusses that the radiation power is controled by the slot offset and angle. The thickness of the waveguide wall is also discusses in the analysis.

• Journal of electromagnetic engineering and science
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• 제1권2호
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• pp.161-165
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• 2001

The radiation characteristics of leaky wave emanated from finite strip-grating loaded dielectric coated coaxial waveguide with finite periodic thick slots are investigated theoretically. The rigorous integral equations are derived for the proposed structure using the courier transform, mode expansion, and sine series expansion of the electric current on metallic strips, and the simultaneous linear equations are obtained. The effects of finite strip-grating loading on a dielectric-coated coaxial waveguide with finite periodic thick slots are examined in terms of radiation characteristics.

• 한국전자파학회지:전자파기술
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• 제2권4호
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• pp.33-37
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• 1991

플란지 평행판 도파관의 복사문제를 고찰한다. 푸리에 변한 기법을 사용하여 복사장을 주파수 영역에 표시한 다음, 근사우열로써 복사장을 구한다. 구해진 복사장을 다른 기법에의해서 구해진 해와 비교하여서, 기존 해의 타당성을 검토한다.

• 전기학회논문지P
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• 제58권4호
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• pp.461-464
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• 2009

The characteristics of slow wave structure employed for backward wave oscillators expected to be a high power microwave source are studied analyytically. The slow wave structure is a sinusoidally corrugated wall waveguide. The waveguide is designed and fabricated by cast aluminun. The dispersion relation and transmitted characteristics for microwaves are measured in the air. There exist literatures on high efficiency of enhanced radiation from backward wave oscillators involving plasma studied experimentally.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.1-8
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• 2017

This paper introduces a technique to obtain the broadband characteristics of circularly polarized antennas using an L-shaped probe. A waveguide antenna is suitable for obtaining high gain and handling convenience in some applications; however, the asymmetrical structure of the L-shaped probe results in cross-polarization and frequency dependence on the field distribution of higher-order modes (HOM). In addition to the basic characteristics of a waveguide antenna with an L-shaped probe, the author discusses some techniques to reduce the HOM and cross-polarization. As a result, the 3-dB axial ratio (AR) is obtained with the fundamental mode even when the frequency is expanded to the region for HOM of TM. This reduction is mainly due to the cutoff structure to the TM mode around the short wall of the waveguide. Furthermore, some aperture modification techniques can reduce the cross-polarization in a wide range of angles in the radiation pattern. Such techniques and their mechanisms are discussed in this paper. The obtained performance shows that the proposed antennas have a wide range of angles of 3-dB AR in the radiation pattern, broadband characteristics in impedance and AR, and low variation in group velocity.

• 전자공학회논문지A
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• 제32A권7호
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• pp.23-29
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• 1995

A characteristic mode theory for longitudinal slot of arbitrary width in the outer conductor of coaxial waveguide is applied for calculating the characteristic magnetic currents, the characteristic fields, radiation patterns, and the fields evershere(inside and outside the guide, and in the aperture region). Numerical results of the equivalent magnetic currents and the radiation patterns are compared with those obtained by use of the method of moments.

• 한국전자파학회논문지
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• 제19권11호
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• pp.1294-1302
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• 2008

이중 편파 특성을 갖는 위상 배열 안테나에 사용될 수 있는 도파관형 방사 소자의 설계 방법을 제시하였다. 소형화를 위하여 리지 형태의 도파관을 사용하였고, 이중 편파를 위해서는 도파관 내에 인쇄된 다이폴 구조의 마이크로스트립 형태를 부가적으로 추가하는 형태를 취하였다. 설계 방법의 타당성 검증을 위하여 $1{\times}4$ 배열 안테나를 제작하여 반사 손실, 인접 채널간 동일 편파 상호 간섭 및 복사 패턴을 측정하여 이론치와 비교하여 잘 일치함을 확인하였다. 본 논문에서 제시한 구조는 이중 편파 특성을 갖는 위상 배 열 안테나의 단위 소자로서 유용한 구조로 사용될 수 있을 것으로 생각된다.

• 한국전자파학회논문지
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• 제22권1호
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• pp.59-66
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• 2011

본 논문에서는 높은 방사 효율을 갖는 co-planar waveguide(CPW) 급전 방식의 영차 공진 안테나를 제작하고 측정하였다. 제안된 안테나의 단위 셀은 직렬 metal-insulator-metal(MIM) 형태의 커패시터와 단락된 병렬 스터브 인덕터로 구성되어 있다. 안테나의 크기를 소형화시키는 동시에 방사 효율을 높이기 위하여 비아를 통하여 접지면과 연결되어지는 두 개의 $90^{\circ}$ 접혀진 단락 스터브 선로를 병렬 인덕터의 구조로 사용하였다. 두 개의 단위셀을 사용하여 설계된 안테나는 composite right/left-handed(CRLH) 전송 선로의 끝단을 개방하여 병렬부에서 주된 방사가 일어나도록 하였다. 제안된 안테나의 영차 공진 주파수는 3.05 GHz이고, 전체 크기는 $0.22\;{\lambda}_0{\times}0.22\;{\lambda}_0$이다. 제작된 안테나의 측정 결과, 영차 공진 주파수 2.97 GHz에서 안테나의 이득과 효율은 각각 3.04 dBi와 75 %로 향상되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.880-882
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• 2004

This paper presents the design and simulation results of 7 waveguide dielectric rod array antennas for 7 channel DBF(Digital beamformer) receivers for stratospheric system. A waveguide. dielectric antenna type, which has FTEP(Flat-toped element pattern) to manufacture easily. Also, the calculated element patterns according to the permittivity are compared. The designed antenna will be used for generating multibeam radiation pattern by means DBF.

• 전자공학회논문지A
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• 제28A권10호
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• pp.799-805
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• 1991

In this paper, the analysis and design of a spirally slotted array antenna with high efficiency are presented. Electric fields in the slots are calculated by electromagnetic fields in the upper waveguide and radiation field equations are derived. Slots are arrayed spirally on the upper circular plate of twofold radial waveguide. In order to suppress grating lobes from the array, a slow wave structure is inserted in the upper waveguide. This antenna is characterized by a good circular polarization, high efficiency of 75 percent and grating lobes below -34dB.