• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.39-44
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• 2002

A high speed data link capability is one of the critical factors in determining the performance of the spaceborne SAR system with high resolution because of the strict requirement far the real-time data transmission of the massive SAR data in a limited time of mission. In this paper, based on the data lint model characterized by the spaceborne small SAR system, the high rate multi-channel data link module is designed including link storage, link processor, transmitter, and wide-angle antenna. The design results are presented with the performance analysis on the data link budget as well as the multi-mode data rate in association with the SAR imaging mode of operation from high resolution to the wide swath.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.147-151
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• 2000

This paper presents an analysis of a slot on the broad wall of a rectangular waveguide using the 3D FDTD method. In order to reduce the reflection loss, Mur's 2nd absorbing boundary condition is used. To realize the optimum design by FDTD, the effects of time step, excitation aperture size, analysis region and excitation position in model are derived. The analysis results are compared with the experimental results and they show a good agreement with each other.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.7
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• pp.598-609
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• 1991

A generalized expression of radiation intensity from multiple non linear transmission lines is derived from the circuit model of radiation phenomena and the phased array antenna theory, for PC traces having independent signal sources. An adequacy of this proposed analitical method was verified comparing with computer simulation and experimental result for two and three non linear transmission lines feeded by 600 MHz signal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.383-385
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• 2017

For the purpose of providing high data rate real-time services, radio transmission technologies for ship ad-hoc network based on the Recommendation ITU-R 1842-1 are designed. In order to increase the link throughput of real-time services, in this paper, we investigate the performance of the SANET with the spatial transmit diversity techniques are employed. Based on the analysis of the packet error rate and throughput, we select the efficient multiple antenna schemes for SANET to improve the link reliability.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.156.5-156
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• 2001

Stabilized tracking platform in a missile consisting of a flat planar antenna, pitch/yaw gimbals, gear trains, and current controlled DC drive motors for pitch and yaw gimbal must have a capability to track a target as an inertial sensor in the presence of missile body motion such as maneuvering and vibration. Because of this reason, tracking a target from dynamic platform requires a servo architecture that includes a outer tracking loop(position loop) and inner rate loop that stabilizes the line of sight(LOS). This paper presents a gimbaled platform model including nonlinear phenomena due to viscous and Coulomb friction based on experimental data and torque equilibrium equation, the design concept for the inner tacholoop having P controller structure ...

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.621-626
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• 2005

With precise GPS carrier positioning result, we can get attitude information if GPS antenna has adequate attaching position on the vehicle. In this case, baseline length information can be bandied as an additional measurement or constraint. In this paper, we have proposed a method to improve the attitude accuracy. To overcome nonlinearity of baseline observation model, we analyze attitude estimation result using existing estimation method like a least square method and Kalman filter, and apply a new nonlinear estimation method an unscented Kalman filter Finally we confirm the improvement of attitude estimation result in the case of appling the unscented Kalman filter.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.609-612
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• 2003

For combating multipath fading in wireless radio environment, diversity schemes is useful. In this paper, for performance improvement of polarization diversity system, we analyzed a two-branch polarization diversity at the receiving end of a mobile link when the transmitter emits a circularly polarized wave. And In order to calculate the correlation coefficient considering the XPD(cross polarization discrimination) between the received signals for the two diversity branches, a simple theoretical model of circular polarization diversity is adopted and calculate correlation coefficient. From the analysis results, it is seen that the correlation coefficient of circular polarization diversity evaluated by the XPD is less than that of vertical polarization diversity. And also, we designed and fabricated circular polarization diversity system with microstrip antenna. we analyzed data measured in indoor NLOS environment using fabricated circular polarization diversity system. From the measurement results, it is clearly seen that the diversity effect of circular polarization diversity system is higher 3dB than vertical polarization diversity system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1680-1684
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• 2010

CBTC(Communication-Based Train Control) system which is based on wireless communication can provide high density operation of the train using location tracking between ground and onboard train. It can also reduces maintenance expense because it does not require the ground equipment for tracking circuit and signal flag and so on. Recently, research and interest have been done on CBTC system. The high-speed trains up to 300km/h experience multi-path fading channel which bring about the performance degradation of wireless CBTC system. In this paper, we consider MIMO (Multi-Input Multi-Output) antenna-based CBTC system for trains with Alamoutip-type space-time diversity transmission for reliable communication. Also we model a channel considering practical environment and evaluate performance improvement of proposed CBTC system.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.161-168
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• 2014

A real-time monitoring of immersed antenna type inductively coupled plasma (ICP) was done with a homemade 2 dimensional voltage probe array to check the uniformity of the plasma. Measured voltage values with a high impedance voltmeter are close to the floating potential of the plasma. As the substrate carrier was moving into a magnetron sputtering plasma diffusive from a $125mm{\times}625mm$ size cathode, measured results showed reliably separation of plasma into the upper and lower empty space over the carrier. Infra red thermal imaging camera was used to observe the cross corner effect in situ without eroding a target to the end of the usage. 3 dimensional particle trace model was used to analyze the magnetron discharge's behavior.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6C
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• pp.547-553
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• 2010

In this paper, novel approximated closed-form expressions of the SER(Symbol Error Rate) and BER(Bit Error Rate) are presented for the multi-input multi-output space-time block coding(MIMO-STBC) system employing two transmit and N receive antenna(s) in Rayleigh fading channels. Assuming a zero-forcing equalizer and a single-symbol maximum-likelihood (ML) decoder, the formulas are derived for the SER and BER, and then their approximated counterparts are also derived. In the derivation of the approximated expressions, acurve-fitting model is adopted that can eliminate the integral operators in the exact expressions.