• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.954-964
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• 2015

In this research, an overlapped illumination model was newly proposed for designing a freeform LED lens with a uniform illuminance distribution on its illuminating plane. Based on the proposed model and conventional illumination models, freeform lenses were designed and their performances and tolerances were compared. As a result of the tolerance analysis about thickness change in lens, position, size change, central direction change of light emission and characteristic change in LED source. This proposed model and divergent illumination model are similar to the performance about central direction change of light emission in LED source. but the uniformity illumination value in this proposed model is more remarkably value than it in divergent illumination model about characteristic change in LED source.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.32-37
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• 1989

The design method of the center-fed resonant type slotted waveguide antenna using the Dolph-Tschebyscheff array is presented. Slot admittances are obtained by empirical and theoretical method since the effect of mutual coupling between slots is included. We design a slotted waveguide antenna which has 1.8ft. length and operates on 9.4GHz. The experimental results of the antenna show that its gain, maximum sidelobe level and half power beam-width are 25.5dB, -22dB and 3.6deg., respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.3
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• pp.50-57
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• 2008

A telemetry ground station has a highly directional, parabolic tracking antenna to receive a weak telemetry signal from a target at a distance. The tracking antenna with narrow beam-width normally uses the auto-track method for the target tracking. This paper presents several issues in the auto-track method and introduces a new tracking method using Self-Slaving technique. Self-Slaving means that the tracking antenna is slaved to not data measured by RADAR but GPS/INS informations received by the telemetry system for pointing. The Self-Slaving method shows good performance in comparison with auto-track method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.950-957
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• 2012

In this paper, a small round-ended slot loaded by double ridges on the broad wall of a rectangular waveguide is presented as an element for a waveguide slot-array antenna(WSAA). By properly adjusting the ridge dimension, a resonance of the slot at a desired frequency can be achieved. The resonant length of the proposed slot is about $0.26{\lambda}_0$(free space wave length) at the resonance frequency. The proposed resonant slot has some advantageous properties, such as small size, small resonant conductance, and short and stable resonant slot length. In addition, the characteristics of the slots are slightly affected by the adjacent elements when the slots are arrayed for a waveguide slot antenna. A $4{\times}1$ WSAA with -20 dB side-lobe level(SLL) is designed, fabricated, and tested experimentally. The measured results are well agreed with the simulated ones and have an SLL of -15.9 dB and a half-power beam width of $110.2^{\circ}$ in the E-plane and $21.2^{\circ}$ in the H-plane, respectively, at 9.41 GHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.61-70
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• 2008

This paper designed the antenna for collecting and servicing the traffic information that apply to freeway Traffic Management System, as using DSRC (Dedicated Short Range Communication). Active DSRC is the technology that is using 5.8GHz Radio Frequency to a mean Sequency and there are a lot of the case occurring a physical electric wave shadowing because of the traveling straight of a electric wave. In such inferior communication environment, it constructed the stabilized communication link that can do collecting and servicing the correct traffic information and designed the beam pattern considering the establishment position of the antenna that can apply to various road environments and a communication area. By considering the communication link environment, this paper designed and manufacture the mean frequency of 5.8GHz, the input loss of -17dB in 75MHz bandwidth, the Axial ratio of 1.5:1, and $2{\times}4$ array microstrip antenna which beam pattern have the characteristic of $55^{\circ}$ horizontal half power beam width and $26^{\circ}$elevation half power beam width and the minimum establishment height of the antenna was designed as 14m for avoiding electric wave shadowing on a physical condition between vehicles

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.144-150
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• 2012

In this paper, circularly polarization patch array antenna of RSE(Road-side Equipment) base station for DSRC(Dedicated Short Range Communication) of ITS(Intelligent Transport System) is proposed. The antenna of RSE base station for DSRC is designed to operate circularly polarization to receive reflected signal from multiplex path effectively. The proposed antenna consisted of microstrip patch and feed line, the slit is inserted in the proximity of the slot of feed structure to generate circularly polarization. The $2{\times}2$ array structure is designed to satisfying gain that DSRC RSE base station antenna required. Measured impedance bandwidth and axial-ratio bandwidth are satisfied by all DSRC band of 5.795~5.855 GHz. Vertical and horizontal HPBW of the proposed antenna are both about 43 degrees, it showed gain characteristic of about 11.21 dBi.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.157-164
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• 2017

In this research, the overlapped illumination model was used for designing a freeform LED lens with a uniform illuminance distribution on its illuminating plane, and their performances and tolerances were compared. And, the illuminations on a illumination plane was measures for change with average illuminance and illuminance uniformity. As a result of the tolerance analysis about z-axis direction change, thickness change in lens and tilt change of light emission and characteristic change in LED source, overlapped model and divergent illumination model are similar to the performance about Z-axis direction change of light emission in LED source. but the uniformity illumination value in this overlapped model is more remarkably value than it in divergent illumination model about thickness change in LED lens. Also, even though the lens based on a divergent illumination model showed good performance compare to the lens based on an overlapped illumination model, the latter was less the deviation to variation of LED beam radiation ability.

• Journal of IKEEE
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• v.26 no.1
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• pp.137-140
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• 2022

In this paper, we proposed a new W-band monopulse tracking system based on reflectarray antenna structure. The proposed reflectarray antenna monopulse tracking system consists of four feed horn antennas and a planar reflector using a microstrip reflectarray. The four feed horn antennas have a gain of 10 dBi and a half-power beam-width of 56 degrees symmetrically in the E/H plane. It was confirmed that the reflectarray antenna using one feed horn antenna has a size of 41.8 × 41.8 mm², a gain of 26.8 dBi, and a half-power beam-width of about 5.6 degrees. The reflectarray monopulse tracking system using 4 feeding horn antennas is well matched from 75 GHz to 90 GHz, and the isolation is secured by more than 10 dB. Finally, the proposed system shows the tracking range of 5.98 degrees and the tracking error range was 0.02 degrees.