• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.642-646
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• 2016

A wearable antenna made using conductive tape on paper is presented in this paper. The proposed antenna is composed of a half-wavelength conducting dipole strip and a parasitic conducting strip on the A4 copy paper. The antenna is fed at the center of the dipole strip by an SMA connector. The configuration of the proposed antenna changes according to the origami method. Therefore the radiation patterns of the antenna vary according to whether or not the paper is folded. This approach solves the problem that the reception ratio of the signal decreases because of null points in the antenna radiation pattern. The reflection coefficient and the radiation pattern of the proposed antenna at 900 MHz are evaluated using an EM simulation and measurements. It was shown that the proposed paper antenna has reconfigurable characteristics at 900 MHz when utilizing the origami method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.32-38
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• 2014

In this paper, we design a secant pattern antenna combined with a septum circular polarizer to be used in the satellite data communications. To generate a radiation pattern with secant type, Fourier relationship between current distribution and space factor is applied and the circular symmetric structure of the aperture simplifies the design. The optimization process is performed by combining the radiator with the septum circular polarizer, and it is confirmed that the designed radiation pattern, axial ratio, and return loss characteristics satisfies the required performance of the antenna.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.563-570
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• 2022

We designed a biconical antenna with sleeve baluns that exhibited an improved radiation pattern from 3-40 GHz. In the antenna, the edges of the ring of the upper cone are blended to a cylinder. Sleeve baluns operating at specific frequencies are connected to the antenna to minimize leakage currents on the surface of the feeding coaxial cable. The radiation pattern was improved with the sleeve baluns, and the angular 3-dB beamwidth ranged from 67.1-101.1° over 3-40 GHz, which is much broader than the 21-99° of the conventional antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.720-731
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• 2005

In this paper, radiation patterns of electrically small inverted-F antennas(IFAs) on an electrically large cylindrical conducting body like a satellite launcher are experimentally studied. First, radiation patterns are obtained by using method of moment and a commercial software tool, HFSS(High Frequency Structure Simulator) and the results are compared and analyzed with experimental ones. Especially, when the size of a cylindrical conducting body is electrically large, the effects of the size of a cylindrical conducting body on radiation patterns are studied by considering only the partial ground in vicinity of antennas. And then, when one and two inverted-F antennas are on the cylindrical conducting body, radiation patterns are simulated and investigated by using method of moment and HFSS. Good agreements are observed among the results by method of moment, HFSS, and experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.407-416
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• 2021

An active phased array antennas can not only electrically steer the beam by controlling the weighting of the excitation signal, but can also form a pattern null in the direction of the interference source. The weight of the excitation signal to steer the main beam can be easily calculated based on the position of the radiating element. In addition, the weight of the excited signal for pattern null formation can also be calculated by setting the required radiation pattern and using WLSM(Weighted Least Squares Method). However, in a general wireless communication network environment, the location of the interference source is unknown. Therefore, an adaptive pattern null synthesis is needed. In this paper, it was confirmed that pattern null synthesis according to the required radiation characteristic was possible. And based on this, adaptive pattern null synthesis into the direction of an interference source was studied using a binary search algorithm based on observation area. As a result of conducting a simulation based on the presented technique, it was confirmed that adaptive pattern null forming into the direction of an interference is possible in efficient way.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.11
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• pp.33-41
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• 2007

Effect of finite substrate plane on the radiation characteristics of microstrip patch antennas is investigated. The variation of the characteristics of the radiation pattern due to the change of the length of a substrate is much larger than that due to the change of the width of a substrate. As the thickness of a substrate increases, the characteristics of the radiation pattern reveal more sensitive for the change of the size of a substrate.

• The Journal of the Acoustical Society of Korea
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• v.23 no.3
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• pp.197-205
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• 2004

This paper represents the results of interpretation on the cause of sign changing of the striation slopes appearing in the range-frequency domain spectrogram of ship-radiated noise measured in a shallow sea. Striation patterns and dispersion characteristics simulated from a numerical model based on mode theory at various seabed conditions show that the sign changing of the striation slopes appearing in measured signal is caused by the shear property of seabed. more specifically by the shear property of the basement lying below the sediment which is estimated about 3±1m thick.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2246-2252
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• 2009

A new metamaterial antenna with dual resonant modes is presented using an asymmetrical periodic arrangement for orthogonal radiation patterns. The proposed antenna produces two orthogonal modes by the asymmetrical periodic unit-cell arrangement. The orthogonal resonant mode provides perpendicular radiation patterns without changing the antenna polarization at each resonant mode. The fabricated antenna shows good agreements with the theoretical analysis of the electric-field. The experimental results shows the orthogonal radiation patterns along x- and y-axises, and gains are 3.34 and 3.86 dBi at each radiating resonant mode, respectively. Additionally, slotted ground structures are embedded on the back side of the antenna in order to reduce the size and enhance the radiation efficiency of 12 % and 27 %, respectively.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.471-474
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• 2004

본 논문에서는 유전자 알고리즘을 이용하여 소자간의 상호결합이 고려된 경우 빔 패턴 오차의 허용범위를 만족하는 개별소자의 허용오차를 분석하였다. 소나 배열을 통한 빔 패턴은 개별소자에 인가되는 가중치 뿐 아니라 소자간의 방사임피던스 즉 자기방사 임피던스와 음원 상호간의 음향적 간섭에 의한 상호방사 임피던스에 따라 달라진다. 본 논문에서는 유전자 알고리즘을 이용하여 상호결합이 있는 경우에 대해 1 차원과 2 차원 배열에서 주어진 빔 패턴 허용 범위를 만족하는 각 소자별 허용오차 분석하였다.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.3-5
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• 2002

최근 기계적으로 빔을 움직일 수 있는 마이크로 스트립 패치 배열 안테나가 MEMS 기술을 이용해서 제작되고 시험되었다. 본 논문에서는, 제작된 안테나의 적용 예로써 위상변위기를 사용하지 않는 새로운 어레이 안테나의 방사패턴 합성방법을 제안하고, 제안된 방법을 원하는 빔 형상합성에 적용하였다. 방사패턴 형상의 최적화에는 Restricted Competition Selection(RCS)를 이용한 유전 알고리즘을 이용하였다. 또한 이러한 방식의 접근은 EMC 표준에 대처하기 위한 배열 안테나의 설계 시에도 적용이 가능하며, 제안된 방법을 이용하여 특정한 빔 형상들에 대한 합성이 가능하다.