• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.67-75
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• 2008

The electrostatic charging/discharging mechanism and its effects, and the system design considerations in the space plasma environment are studied in this paper. The electrostatic discharge (ESD) effects are carefully taken into account for a design of the satellite system at the early stage of the development. Generally, the electrical design requirements are specified to protect the satellite system from the ESD effects in the electromagnetic compatibility specifications. Those requirements are included the grounding, the bonding, the shielding, the conductive coating, the electric interfacing and so on. The space charging is caused by the increasing of the voltage difference between the each locations on the satellite surface. If the space charging is continued up to threshold, it may be occurred the system failure. This phenomenon is depended on the mission of system, electrical and mechanical configuration, system operation, and orbit condition. Therefore the related requirements are properly tailored and concentrated into the safety design.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.119-128
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• 2004

Recently, the accidents on the sea have arisen due to the increase of the nautical traffic and the digitization of equipments for marine. Therefore, IMO(International Maritime Organization) have provided the recommendation of EMI and EMS for radio communication and equipments of marine from SOLAS convention at July 1st 2002. In this paper, we measured EMC environment on the Hanbada, which is Korea Maritime University training ship, for basic EMC environment of ship. The measuring point was Bridge and Engine Control Room of the ship, we measured at the test point that was set at random. Measured Band is from 30 MHz to 2 GHz, polarization measurement is processed both vertical and horizontal polarization. We analysed the results in consideration of permissible criteria.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.10
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• pp.97-104
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• 2003

This paper addresses EMC test results for the EQM Communications & Broadcasting Satellite(CBS) Ka-band Payload System. The aim of the EMC test is to verify that the payload system has no effect on the other system and is not affected by the external field. The compliance of EMC system requirements was verified by the analysis and measurement of the emission level from the payload system. The variation of performance by noise injection was measured to inspect the susceptibility of the payload system. The analysis and test results also showed that the electromagnetic interference has no serious effect on the overall payload system performance. It is confirmed that the EQM CBS Ka-band payload system can be operable in the space environment from the EMC performance's viewpoint. It is also obtained that better performance can be acquired by improving waveguide design and integration method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.148-156
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• 2003

This paper describes the RF performance issues of UE for W-CDMA system based on 3 GPP specifications. The parameters of transmitter and receiver are derived from the viewpoint of RF performance. In order for UE to achieve high performance, the transceiver performance requirements such as ACLR, EVM, Peak Code Domain Error, spectrum emission mask, frequency error stability and TX power control dynamic range for transmitter and reference sensitivity level, blocking characteristics, noise figure, ACS, AGC dynamic range for receiver are considered. On the basis of the required parameters, the UE RF transceiver is implemented and then the evaluation of RF performance is accomplished through practical test scenarios.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.437-443
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• 2003

A interference of outside electric source and electric fast transient(EFT) are origins of destroy and malfunction in the precise electrical and electronic equipments. It makes a serious obstacle as the form of conducted noise. Therefore, it is strongly needed to protect precision electrical and electronic equipments from the interference and EFT. In this research, a EMC filter composed of feed-through capacitors and ferrite beads of high permeability is designed and it＇s properties are investigated for PDP. The filter produced in this research have wide band frequency characteristics and more than 40 dB reflection loss in the frequence of 10 MHz∼1.5 GHz which satisfy the standard of CISPR Pub. 22 and the level 4 of IEC 61000-4-4.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.730-735
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• 2004

This paper describes what brings about DC offset and the impact or the DC offset on the performance or direct-conversion mobile receiver in WCDMA system. The performance degradation of $E_{b}/N_{o}$ due to the DC offset is presented through simulation result. Direct-conversion RF Transceiver which has the function of DC offset control is implemented and then applied to the WCDMA test-bed for the performance evaluation. The receiver performance degradation of $E_{c}/I_{o}$ is evaluated and analyzed by varying DC offset value. The practical test showed the minimum requirement of DC offset value to meet system performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1282-1290
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• 2000

The LHCP circularly polarized antenna operating at the satellite broadcast receiving band is developed by employing the sequential-rotation technique in which each truncated-corner patch square element is arranged in the triangular lattice type. Antenna designed with sequentially rotated technique of triangular lattice type has the effect of improved axial-ratio bandwidth, cross-polarization etc., and the degradation of radiation pattern can be reduced significantly by minimizing the radiation loss of feeding line structure. Characteristics of antenna designed is satisfied with specifications of array antenna for DBS that is -27 dB of side lobe level and -20 dB of cross-polarized level at $\Phi$=45$^{\circ}$ plane.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.723-730
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• 2007

This paper shows how the ACLR of power amplifier can be reduced by using Anti-phase IMD linearization technique which generate anti-phase IMD in the driver stage compare to output stage's IMD. And design process proposed. From the experimental result of W-CDMA 4FA input signal, this amplifier has ACLR -55 dBc@5 MHz offset at 30 watts average power. Compare to optimum matching technique to get maximum power gain, this technique has been improved ACLR by 12 dBc. Also this amplifier meets 50 watts average output power amplifier specification in domestic market.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.3
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• pp.170-176
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• 2017

In this paper, we proposed the miniaturized structure of the Log-Periodic Dipole Array(LPDA) antenna for PS-LTE(Pubic Safety-Long Term Evolution) service. The length of array dipole was shortened by adding a fractal tree element with iteration to the array dipole to miniaturize the LPDA antenna. As the result, the proposed LPDA antenna was reduced up to 25 %, compared a typical LPDA antenna. To validation of the proposed LPDA antenna specification, the proposed LPDA antenna is fabricated using aluminum with 1.5 mm thickness and performances are measured. Comparison between simulation result and experiment shows good agreement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.612-619
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• 2016

In this paper, a dual band electrical beam tilting array antenna with bi-directional directivity is designed. Radiating element operates at dual-resonance frequencies and is designed as planar dipole using PCB. In order to tilt the main beam, the phase delay line is designed by use of only the phase shifting line of a $50\Omega$ microstrip line for broadband. The designed antenna has tilting angle of $0^{\circ}$ to ${\pm}8^{\circ}$. For validation of the designed antenna specification, the array antenna is fabricated and the performances are measured. Comparison between theory and experiment shows good agreement.