• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.517-522
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• 2013

The spurious electromagnetic radiation is generated due to the RF unbalanced current on a conductive cable connecting an electronic device to another. A metamaterial-based filtering geometry with frequency selectivity is suggested to reduce the radiation with a bandgap structure, where the right-handed inductance and capacitance stem from the transmission-like configuration between the cable and the metal protrusion, and the left-handed components come from the narrow cavities. The effect of the structure on the unbalanced current pulse and its spurious radiation is presented in the FDTD-method frame work.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.225-230
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• 2012

The Korean nationwide differential global positioning system (NDGPS) reference station transmits a global positioning system (GPS) enhancement signal using minimum shift keying modulation with a 200 bps data rate. The ocean-based DGPS covers the service area of 100 NM with 300 W output power; on the other hand, the land-based DGPS transmits the output power of 500 W, which covers the service area of 100 km. The DGPS reference stations with high output power can radiate spurious signals, which may act as interference sources affecting the other DGPS reference stations or the wireless ground stations that utilize the medium frequency band. In this paper, the radiation spectrums of the DGPS reference stations are measured and analyzed in the spurious domain. The DGPS radiation spectrums are evaluated from the perspective of the interference effect.

• Journal of electromagnetic engineering and science
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• v.5 no.2
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• pp.97-103
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• 2005

This paper describes the measured results of sonobuoy transmitting antenna system for anti-submarine warfare (ASW). Since radiation pattern and power density depend on impedance matching between transmitting RF part and antenna with termination resistance, design of matching circuit is very important for sonobuoy system performance. Matching circuit is designed by Smith chart using control of L and C. In standing wave ratio(SWR) measurement using Network Analyzer, SWR of antenna with matching circuit observed 1.5 below at the assigned VHF band. It shows very excellent performance comparison with conversional product that is used for the same object. The measured vertical and horizontal radiation patterns are also shown the satisfaction of military specifications. A drop out of sonobuoy system on the sea is happened when angle of elevation direction is over 10 degrees, and it is conformed that it takes less than I second return to original signal level. The required electric power density is $83\;mW/m^2$ in the military specification, and measured electric power density is observed over average $110\;mW/m^2$ at all frequency bands.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.398-401
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• 2002

본 논문은 최근 사용이 증가하고 있는 1㎓ 이상 장해파의 허용 기준안을 정하기 위한 측정에 이용되는 피시험체의 최적 회전 스텝 크기를 결정하고 방사 패턴의 측정 및 결과를 나타내었으며 기가헤르츠 대역의 CISPR 허용기준치와 비교하였다. 실제 피시험체를 측정한 결과, 가장 좁은 3㏈ 빔폭은 수평편파에서 약 18도, 수직편파에 대해 약 20도 정도이다. 최대 방사 방향에서 3㏈ 빔폭의 경우 수평편파에서는 60도이며 수직 편파에 대해서는 50도를 보였고, 적절한 스텝 크기는 40개였다. 또한 CISPR에서 제안한 허용기준치에 측정값이 만족하는 것을 알 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.1-7
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• 2013

The interference among the rain radars and interference in the adjacent wireless station due to the spurious signals from the rain radar were analyzed in this paper. The rain radar measures the rain intensity using S-band signal. The measured data are utilized in forecasting the rainfall. The interference among the rain radars or in the adjacent wireless stations may be caused by the operation with low elevation angle and the high output power. Based on the propagation analysis of S band signal and the deduced interference protection ratio of rain radar, the interference due to the rain radar are analyzed. Also, the radiation spectrum characteristics of a rain radar are deduced from the caused interference effects by the spurious signals of the rain radar. To minimize the interference effects for adjacent wireless stations, it is required to get the rejection characteristics of spurious signals above 105 dB. In viewpoints of interference for rain radars, it is necessary to operate the rain radar with a different PRF and operation time opposite to adjacent rain radars.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.553-556
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• 2012

The interference among the rain radars and interference in the adjacent wireless station due to the spurious signals from the rain radar were analyzed in this paper. The rain radar measures the rain intensity using S-band signal. The measured data are utilized in forecasting the rainfall. The interference among the rain radars or in the adjacent wireless stations may be caused by the high output power of rain radar. Based on the propagation analysis of S band signal and the deduced interference protection ratio of rain radar, the interference due to the rain radar are analyzed. Also, the radiation spectrum characteristics of a rain radar are deduced from the caused interference effects by the spurious signals of the rain radar.

• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.109-118
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• 2001

KITSAT-1, launched in 1992, passes through Inner Van Allen Radiation Belt in which high energy Protons cause single event upsets(SBUs) in the main memory of KITSAT-1 OBC(On-Board Computer) 186. The present paper compares SEU data from the OBC186 with the AP-8 model of NASA/NSSDC using the Chi-Square method to estimate the SEU threshold energy. Shielding effect by the satellite body has been taken into account to model the proton fluxes at the position of OBC186, and SEUs recorded during the high solar activities have been removed to avoid the spurious result. The result shows that the SEU threshold energy of the main memory of KITSAT-1 OBC186 is estimated to be about $110{pm}10MeV$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.981-989
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• 1997

In this paper, the 5-element active phased array antennas coupled through slotline between elements are designed and fabricated. A recent studies on the active phased array antennas using the transmission line coupling which can be designed to provide strong coupling and the appropriate coupling phase. But this sturucture has limitation of expanding in two dimensions for planar active phased array antennas and distortion of the radiation pattern caused by coupling network. Thus our work proposes the slotline coupling structure asthe broadband coupling network for the active phased array antenna. In experiment, 5-elements active phased array antenas have steering range from -30.deg. to 20.deg. off broadside as the free-running frequencies of end elements are controlled. The overall results show that the proposed slotline coupling structure is suited for the coupling network in the actie phased array antenna system. And the proposed coupling structire solves the expansion problem and eliminates the distortion of the radiation pattern caused by the spurious radiation of the transmission line coupling network. Thus thiscan be expanded to two dimensional coupling network for the planar active phased array antenna system.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.4
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• pp.6-11
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• 2001

In this paper, the aperture-coupled U-slot microstrip patch antenna is studied for the bandwidth improvement. The aperture is used as a mechanism for coupling the radiating element to the microstrip feedline, and the aperture-coupled configuration provides the advantage of isolating spurious feed radiation by the use of common ground plane. Experimental results such as return loss, VSWR, radiation pattern and gain measurements are presented on the aperture-coupled U-slot microstrip patch antenna. The impedance bandwidth (VSWR≤2) of the antenna is 6.4% centered at 2.35GHz, and the average gain is 5.3 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.8-13
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• 2003

In this paper, suitablility of 1 GHz CISPR limits establishment fur broadcast communication quality protection is examined and the optimum turn step resolution of EUT for spurious measurement of frequency above 1 GHz to increase the accuracy of maximum values extraction is examined. As a result of 500 MHz and 1.7 GHz clock speed personal computer of micro-processor measurement, optimum turn step resolution extracted by National Institution of National Instrument of Standard & Technology(NIST) Koepke method is estimated 40 table positions per polarization in 500 MHz. And in case of 1.7 GHz, step size is 36 table positions. Prediction of turn step size required for fully scan method in gjgahertz measurement will increase measurement accuracy and reduce considerable measurement time as well.