• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.121.3-121
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• 2001

The movement of a ship is important for DBS(Direct Broadcasting Satellite) Receiving Antenna control algorithm design on shipboard. Especially, turning of ship is essential factor to affect the angle change of azimuth and elevation. Therefore, to track the satellite stably, we need the tracking method considering turning rate of ship. In this paper, we propose an effective satellite tracking algorithm for DBS receiving antenna on shipboard. In the proposed method, when a ship is turned, it selects one of the Multi tracking modes - Normal mode, Low speed mode, Middle speed mode and High speed mode - according as turning rate to be calculated by using Gyro sensor.

• 전기학회논문지
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• 제57권5호
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• pp.816-820
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• 2008

The RF inductive discharge of inductively couples plasma (ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. Although most practical ICPs operate at 13.56 [MHz] and 2.65 [MHz], the trend to reduce the operating frequency is clearly recognizable from recent ICP developments. In an electrodeless fluorescent lamp, the use of a lower operating frequency simplifies and reduces cost of RF matching systems and RF generators and can eliminate capacitive coupling between the inductor coil and plasma, which could be a strong factor in wall erosion and plasma contamination. In this study, We discussed simulation and experimental results when changing ferrite position in antenna.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권5호
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• pp.177-181
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• 2003

Partial discharge pulse shapes from variable PD (partial discharge) sources sustain many characteristics such as types of PD. Ultra high frequency antennas have wide bandwidth from 30KHz to 2㎓. Therefore, signals taken from a UHF antenna have important attributes (rising time, falling time, shape factor, etc.) for electromagnetic sources, such as PD sources. We investigated PD pulse shapes from several PD sources using a UHF antenna and the results were used for classification of PD sources. Features for discrimination are extracted from frequency distribution and LPC (Linear Prediction Coefficient) of time signal. RBFN are used for investigating the possibility of classification of multi-PD sources.

• 한국전자통신학회논문지
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• 제15권1호
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• pp.15-20
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• 2020

본 논문에서는 건물의 실내 환경 전시관과 대회의실에 대한 지연 확산 측정 및 분석하였다. 두 건물의 실내 환경에 대해 시나리오를 작성하였다. 또한, 시스템 구성과 측정 방법을 같은 조건으로 진행하였다. 측정 조건은 중심 주파수인 3 GHz, 6 GHz로 하였고, 분석 대역은 2 GHz로 선정하였다. 측정시스템은 벡터 네트워크 분석기, 전력 증폭기, 무지향성 송·수신 안테나, 전송선로를 구성하였다. 두 건물의 실내 환경 시나리오에 따라 송신 안테나 위치를 기준으로 수신 안테나의 위치를 3개의 구역으로 나누고 각각 18개의 위치에 따라 1 m 간격으로 측정하였다. 두 건물의 전력 지연 프로파일, RMS 지연 확산, K-factor 결과를 비교 분석하였다.

• 한국ITS학회 논문지
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• 제11권1호
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• pp.42-52
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• 2012

본 논문에서는 UWB (Ultra Wide Band) high 대역 (중심 주파수 : 9.5 GHz, -10 dB 대역폭 : 600 MHz, 6.4 %)의 차량 측후방 레이더 센서용 도파관 안테나를 설계 및 제작하였다. 안테나는 대역폭이 넓고 구조가 간단한 프로브 급전 구형도파관을 이용하였다. 본 연구의 차량 레이더 시스템에 있어서 송수신 안테나의 큰 격리도 특성을 얻는 것이 설계의 중요한 변수이다. 따라서 두 도파관 안테나를 E-면과 H-면 배열하였을 시 격리도 특성을 시뮬레이션 하였다. 그 결과 도파관 안테나의 $TE_{10}$ 모드에 의하여 E-면 배열 보다 H-면 배열의 격리도 특성이 우수한 것을 확인하였다. 따라서 H-면 배열된 송수신 도파관 안테나를 T-형 레이더 모듈에 장착하여 안테나의 특성을 검출하였다. T-형 모듈에 장착된 송수신 안테나의 -10 dB 대역폭은 각각 1000 MHz (10.52 %)와 1090 MHz (11.47 %)로 측정되었고 격리도 (S21)는 요구 대역 내에서 -50 dB 이하로 측정되었다. 송수신 안테나의 최대이득은 각각 7.65 dBi와 7.26 dBi로 나타났으며 H-면 빔폭은 $64^{\circ}$, $65^{\circ}$로 측정되어 차량 측후방 레이더 센서용 안테나로 적합함을 확인하였다.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.90-97
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• 2017

In this paper, we propose a new array antenna scheme which has an improved side lobe level (SLL) as well as a simplified feeding network and a high gain. The proposed array scheme is based on a non-uniformly excited sub-array. For analysis, we use an array factor of sub-array antenna. In the simulation results, the simulated SLL and gain provide more than 18.43 dB and 26.63 dBi, respectively. For the verification of the proposed design scheme, the prototype antenna with $16{\times}8$ radiating elements was designed by the proposed array scheme. The measured SLL and gain are more than 19.85 dB and 25.53 dBi, respectively. This measurement result indicates that the proposed array scheme is reasonable.

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.86-91
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• 2010

In this paper, a double-layered frequency selective surface(FSS) superstrate was built and tested. The unit cell of the proposed FSS consists of a ring slot and a dipole-shaped structure and shows a complementary frequency response. Each unit cell is printed on two sides of a substrate. By using these double-layered structures, the first resonant frequency of the pass-band can be lowered. As a result, the size of the unit cell is minimized and the spacing between the other cells is reduced. The proposed FSS-dipole composite antenna is designed for the gain enhancement of wide-band code division multiple access(WCDMA) frequency bands(1.92~2.17 GHz) with a low quality factor(Q=0.17). To verify the gain enhancement performance of the FSS, an FSS-dipole composite antenna was created. Although the FSS layer enhances the gain of the primary radiation source of the dipole antenna, the FSS-dipole complex antenna cannot show a uniform gain over the entire desired frequency band. The experimental results show a gain enhancement of 3 dBi with an FSS superstrate in the WCDMA frequency band.

• 한국통신학회논문지
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• 제30권12A호
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• pp.1161-1167
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• 2005

본 논문에서는 주파수 재사용률이 1인 OFDM(Orthogonal Frequency Division Multiplexing) 기반의 셀룰러 시스템을 위한 가상 스마트 안테나 개념을 소개한다. OFDM 기반의 셀룰러 시스템은 다중경로 채별에 강건한 장점이 있으나, 셀 경계에서 인접 셀에 의한 셀 간 간섭이 큰 단점이 있다. 본 논문예서는 다수의 기지국으로부터 수신되는 OFDM 신호의 심볼 타이밍 오프셋 추정 기법을 유도하고 준정칙 페이딩 채널에서 이러한 심볼 타이밍 오프셋에 의하여 형성된 조정백터(steering vector)을 이용한 가상 스마트 안테나 기반의 셀 간 간섭 제거 기법을 제안한다.

• Journal of electromagnetic engineering and science
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• 제14권3호
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• pp.293-298
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• 2014

Large spaceborne antennas should be lightweight, a factor related to the development costs of launch vehicles. In order to overcome this drawback, a feasibility study of a new carbon fiber reinforced polymer (CFRP) named M55J/RS3 is carried out for a synthetic aperture radar (SAR) reflector antenna. In particular, the high resolution of detected images is taken into consideration. To validate the electrical performance, a test of the CFRP specimen is fabricated, and the transmission/reflection coefficients are measured using a standard X-band waveguide. Finally, the effective complex permittivity and effective electrical conductivity are derived from the obtained measured data. By applying the derived conductivity to the simulation of the radiation pattern, antenna gain, and beamwidth-instead of relying on the assumption of a perfect electric conductor-variations in electrical performance are also investigated and discussed.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.3-6
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• 2008

In this paper, we propose the folded PIFA with its made an alteration to a factor of resonance for L-slot PIFA. Proposed antenna maintain diminished size patch and improve each bandwidth of GSM(0.88$\sim$-0.96 GHz) and W-CDMA(1.92$\sim$2,17 GHz) for miniaturized repeater. The non-slot step folded PIFA's structure that design of essence was general L-slot PIFA for dual-band. It has no U-slot, multi band and the another slot. The parameters of proposed antenna were optimized for dual-band and compact size by folded singleness patch. Proposed antenna by using folded singleness patch take satisfaction main point, bandwidth of GSM and W-CDMA, compact patch size($39{\times}21{\times}13mm^3$). The antenna was designed by FDTD simulation tool and it was made from result of simulation. Measured data shown that the proposed non-slot step folded PIFA was strong possibility.