• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.636-639
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• 1995

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.8
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• pp.864-871
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• 2014

In this paper, we propose an optimization method for obtaining beam curve which minimize the phase errors of Rotman lens. This method is based on idea that 3 path lengths from a beam port through equal phase points, which consist of the center point of array antenna and two points placed symmetrically or asymmetrically along array antenna, to the corresponding phase front are equal. According to this method, the optimal locations of beam ports can be obtained directly by finding each equal phase point set on array antenna to minimize the phase errors for each beam direction. Simulation results show that the proposed method is the most optimal and effective method for determining the beam curve of Rotman lens with low phase errors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5208-5213
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• 2011

In this paper, we proposed a new direction finding(DF) technology using TDOA(time-difference of arrival) and PDOA(phase difference of arriving signal) method. The proposed technology has a good DF accuracy without DF ambiguity. TDOA or PDOA technology is used to the most of intelligence systems in 21 century. The principle of TDOA is to receive a signal with two parallel antennas, measure the time difference of arrival signal, and converse the time difference to the direction of incident signal. Those technology make a DF system small size but the DF accuracy is low into short antenna installation distance. The principle of PDOA is similar to TDOA except measuring the phase difference of arrival signal, These technology get a good DF accuracy in short antenna installation distance but have a DF ambiguity. The proposed DF method is simulated into DF system operation environment with noise, and has a good DF accuracy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.143-152
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• 2019

In this paper, we described the design of Ka-band planar active phased array antenna which is applicable for small RADAR for airborne and seeker of guided missile. The antenna consists of about 1000 array radiating elements and is designed to be within 200mm diameter. We optimized the spacing of radiating elements to allow beem steering above ${\pm}55$ degrees of Field of view, and analyzed the performance of antenna. We confirmed that the Effective Isotropic Radiated Power (EIRP) of the antenna can be 94.22 dBm and receive G/T can be 1.68 dB/k through the designs of RF components and the verification of RF budget. The TX output of TR Module is designed to be over 1.3W for EIRP, and Receive noise figure of TR Module is designed to be less than 5dB for G/T.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.5
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• pp.77-83
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• 2004

Based on a Phased array technology, 2-dimensionally steerable base station antenna was developed at cellular band. The antenna, which consists of 2 by 5 radiating element, can provide 14㏈i gain with half power beam width of 0$^{\circ}$and 13$^{\circ}$ in horizontal and vertical plane respectively. It has beam scanning range of 0$^{\circ}$to 12$^{\circ}$in vertical down tilting and -15$^{\circ}$to 15$^{\circ}$in horizontal steering. The beam control Performance of antenna was verified by DM measurement on field trial.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1027-1035
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• 2016

In this paper, the method to miniaturize the radiating element of a VHF-band active electronically scanned array is proposed. The length of the proposed dipole having trapezoidal shape structure is miniaturized using meander line while the performance degradation is minimized. The grid reflector is used to improve the antenna directivity and insensitivity due to the outer environment. In addition, the antenna is designed to take into account for array application. The fabricated antenna has a 9.1 % fractional bandwidth for the voltage standing wave ratio(VSWR) 2:1 and the maximum gain of 4.24 dBi. The front-to-back ratio(FBR) is larger than 15 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.1007-1019
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• 2006

In this paper, the synthesis method of multibeam radiation pattern with multi-directional beams and nulls is proposed. Genetic algorithm is applied for the optimization of amplitude and phase of the feeding signal into each element that is structured in planar array of single patch antenna with an arbitrary field distribution. To verify the validity of the proposed method, $2{\times}2$ planar array antenna is used for the measurement and the measured far field radiation pattern is compared with the simulation result. As a result, the synthesis of multibeam radiation pattern is implemented by the optimization of amplitude and phase of the feeding signal into each element of $8{\times}8$ planar array antenna system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.4
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• pp.683-690
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• 2018

In this paper, a new signal processing technique is proposed for calibrating gain, phase, delay offsets in array antenna based anti-jamming minimum variance distortionless response (MVDR) global-positioning-system (GPS) receivers. The proposed technique estimates gain, phase and delay offsets across the antennas, and compensates for the offsets based on the estimates. A pilot signal with good correlation characteristics is used for accurate estimation of the gain, phase and delay offsets. Based on the cross-correlation, the delay offset is first estimated and then gain/phase offsets are estimated. For fine delay offset estimation and compensation, an interpolation technique is used, and specifically, the discrete Fourier transform (DFT) is employed for the interpolation technique to reduce the computational complexity. The proposed technique is verified through computer simulation using MATLAB. According to the simulation results, the proposed technique can reduce the gain, phaes and delay offset to 0.01 dB, 0.05 degree, and 0.5 ns, respectively.

• Optical Science and Technology
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• v.5 no.1
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• pp.45-51
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• 2001

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.12
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• pp.1031-1043
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• 2015

This paper describes the pattern synthesis method of two kinds of conformal array antenna using the Enhanced Adaptive Genetic Algorithm (EAGA). One is the $1{\times}16$ conformal array antenna on a curved cylindrical metallic surface with quadratic function, and the other is the 18-element conformal arrary antenna on a metallic surface obtained by the rotation of a quadratic function curve around the axis. The active element pattern is utilized in the pattern synthesis. Especially for the case of the rotated-type conformal array antenna the transformed active element pattern obtained from the Euler's angle rotation of the active element pattern of the planar concentric array is utilized, which reduces the synthesis time a lot. To verify the validity of the proposed synthesis method the MATLAB results are compared with the MWS results. Furthermore, for the case of $1{\times}16$ conformal array antenna the measured results are compared with the MATLAB synthesized results.