• ETRI Journal
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• v.39 no.2
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• pp.234-244
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• 2017

Research interest in three-dimensional multiple-input multiple-output (3D-MIMO) beamforming has rapidly increased on account of its potential to support high data rates through an array of strategies, including sector or user-specific elevation beamforming and cell-splitting. To evaluate the full performance benefits of 3D and full-dimensional (FD) MIMO beamforming, the 3D character of the real MIMO channel must be modeled with consideration of both the azimuth and elevation domain. Most existing works on the 2D spatial channel model (2D-SCM) assume a wide range for the distribution of elevation angles of departure (eAoDs), which is not practical according to field measurements. In this paper, an optimal FD-MIMO planar array configuration is presented for different practical channel conditions by restricting the eAoDs to a finite range. Using a dynamic network level simulator that employs a complete 3D SCM, we analyze the relationship between the angular spread and sum throughput. In addition, we present an analysis on the optimal antenna configurations for the channels under consideration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.115-121
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• 2012

In this paper, the design and fabrication of slot array in the broad wall of the waveguide for Ka-band monopulse radar are discussed. The aperture distributions are designed for the desired antenna gain, beamwidth and Side-lobe Level(SLL), and then slot parameters, such as lengths and offsets, are obtained for corresponding to each slot admittance in the equivalent circuit by using Elliot's array synthesis procedure. MWS-CST simulation shows the return loss below -10 dB, antenna gain above 32 dBi, 3 dB beamwidth of 3.7 degree and SLL of -20 dB. In order to demonstrate the expected results, the designed antenna is fabricated and measured.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.137-144
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• 2009

This paper deals with the performance comparison of jammer signal's angle spreading in the beamforming after the estimation of direction of arrival using 3D array antenna basis of the GPS signal. After the estimation of direction of arrival using array antenna, the beamforming is need for the direction of arrival by spatial filtering and the other direction are nulling for reducing intererence signal, it is possible to improving the received signal strength and quality. But we obtains the degraded performance by the angle spreading due to the multi-jammer signal in this process. In this paper, the MUSIC and LCMV algorithms are applied for the estimating the direction of arrival and for beamforming using the 5 types of 3D array antenna. we performs the comparison of performance by calculating the bit error rate applying the BPSK modem and the varying the azimuth and elevation angle of incoming jammer signal. As a result of simulation, the Curved (B) type 3D array antenna has a more better performance compared to the other type antenna.

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.37-42
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• 2000

In this paper, we propose a super multi-view (SMV) 3-D display system using a vibrating scanner array (ViSA). The parallel beam scanning using a vibrating scanner array is performed by moving back and forth an array of curvature-compensated mirrors attached to two vibrating membranes. The parallel laser beam scanner array can replace the polygon mirror scanner which has been used in the SMV 3-D display system based on the focused light array(FLA) concept. The proposed system has great advantages in the sense that it requires neither huge imaging optics normechanical scanning parts. Some mathematical analyses and fundamental limitations of the proposed system are presented. The proposed vibrating scanner array, after some modifications and refinements, will replace polygon mirror-based scanners in the near future.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.684-689
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• 1990

We design a circular microstrip array antenna using the admittance of circular resonator. We can design the array antenna, considering equivalent radius of circular microstdrip consistant with conductances which are obtained from excitation coefficeients of the array elements. The antenna with 10 array elements are made on teflon substrate from Tshebyscheff method. It's perfermence are the gain 8.9dB, half power beam width 11.3dge, max, side lobe level -19dB, and they are almost in agreement with the theoretical results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1481-1487
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• 2008

In this paper, we propose a novel interactive 3D floating image pointing device for the use of 3D environment. The proposed system consists of the 3D floating image generation system by use of a floating lens array and the a user interface based on real-time finger detection. In the proposed system, a user selects single image among the floating images so that the interaction function are performed effectively by pressing the button event through the finger recognition using two cameras. To show the usefulness of the proposed system, we carry out the experiment and the preliminary results are presented.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1500-1503
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• 2007

Auto-stereoscopic 3D of 60-view number is made using slanted lenticular lens array and LCD of 15.1 inch diagonal size and 3200 by 2400 pixel numbers. Due to its large view number, smooth motion parallax is observed and the visual fatigue is reduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1730-1736
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• 2015

This paper presents a 16-channel transimpedance amplifier (TIA) array implemented in a standard $0.18-{\mu}m$ CMOS technology for the applications of panoramic scan LADAR (PSL) systems. Since this array is the front-end circuits of the PSL systems to recover three dimensional image for unmanned vehicles, low-noise and high-gain characteristics are necessary. Thus, we propose a voltage-mode inverter TIA (I-TIA) array in this paper, of which measured results demonstrate that each channel of the array achieves $82-dB{\Omega}$ transimpedance gain, 565-MHz bandwidth for 0.5-pF photodiode capacitance, 6.7-pA/sqrt(Hz) noise current spectral density, and 33.8-mW power dissipation from a single 1.8-V supply. The measured eye-diagrams of the array confirm wide and clear eye-openings up to 1.3-Gb/s operations. Also, the optical pulse measurements estimate that the proposed 16-channel TIA array chip can detect signals within 20 meters away from the laser source. The whole chip occupies the area of $5.0{\times}1.1mm^2$ including I/O pads. For comparison, a current-mode 16-channel TIA array is also realized in the same $0.18-{\mu}m$ CMOS technology, which exploits regulated-cascode (RGC) input configuration. Measurements reveal that the I-TIA array achieves superior performance in optical pulse measurements.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.363-367
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• 2016

In this paper, we present a resolution-enhanced computational integral imaging reconstruction method by using boundary folding mirrors. In the proposed method, to improve the resolution of the computationally reconstructed 3D images, the direct and reflected light information of the 3D objects through a lenslet array with boundary folding mirrors is recorded as a combined elemental image array. Then, the ray tracing method is employed to synthesize the regular elemental image array by using a combined elemental image array. From the experimental results, we can verify that the proposed method can improve the visual quality of the computationally reconstructed 3D images.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.3
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• pp.245-252
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• 2007

The important problems from the point of view of preventing global warming are to save the power consumption of automotive air-conditioning systems and reduce the refrigerant amount filled. To achieve such requirements, integral receiver/dryer (R/D) condensers were developed recently. Typical integral R/D condensers have extra headers that play the role of R/D. Except an extra header and somewhat complex tube array resulting from the extra header, the most integral R/D condensers have almost the same specification that tube has multi channels, fin has louvers, flow in tube is parallel, etc. When integral condensers are applied, it is known that the refrigerating effect increases, resulting from the increase of subcooling degree in condenser, and the refrigerant amount used saves. In spite of several merits, integral condensers have not been applied a lot. That is why there is an uncertainty in performance, using integral condensers. The objective of this study is to theoretically optimize the tube array in an integral R/D condenser that is really being applied to some vehicles. The tube array has a great effect on the performance of the integral condenser as well as common ones. Through computer simulation, we could see that the tube array, 14-6-3-5-3-4, in the same condenser was the best, comparing heat release rate, pressure drop, etc. to the real array, 17-5-3-3-2-5. It should be noted that the optimization is based on the condenser performance only.