• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.251-257
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• 2015

This work presents modelling and simulation of a readout integrated circuit (ROIC) design considering pair-wise serial configuration along with thermal modeling of an uncooled microbolometer array. A fully differential approach is used at the input stage in order to reduce fixed pattern noise due to the process variation and self-heating-related issues. Each pair of microbolometers is pulse-biased such that they both fall under the same self-heating point along the self-heating trend line. A ${\pm}10%$ process variation is considered. The proposed design is simulated with a reference input image consisting of an array of $127{\times}92$ pixels. This configuration uses only one unity gain differential amplifier along with a single 14-bit analog-to-digital converter in order to minimize the dynamic range requirement of the ROIC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1053-1064
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• 1999

In this paper, to transmit and receive the differently polarized signals simultaneously with a single antenna system, the dual-frequency microstrip array antenna with dual-polarization is proposed and designed. This antenna operates simultaneously at 14.25 GHz and 12.50 GHz. To extend to two dimensional array, microstrip feed line and coaxial probe through via-hole used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.524-527
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• 2000

In this paper, we have studied minimization of the burr which occurred after $\mu$-BGA(ball grid array) singulation process, singulation of the multilayer with a pulsed Nd:YAG(266, 532 nm) laser is used to cut the metal layer which doesn't well absorb laser beam. Especially, the photoresist and $N_2$blowing is effective to minimize of the surface demage and burr. In this experiment, the $N_2$ blowing reduces a laser energy loss by debris and suppress a surface oxidation. The SEM(scanning electron microscopes) and non-contact 3D inspector are used to measure cutting line-width and surface demage. The $\mu$-BGA singulation threshold energy is 75.0 J/cm$^2$at 30 ${\mu}{\textrm}{m}$/s scan speed.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.68-73
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• 2011

This study was performed numerical analysis in order to analyze liquid film flow of heat exchanger tube arrangement and configuration of evaporative multi effect distillation system using medium-temperature. Simulation was accomplished the two-dimensional calculations using commercial analyses program FLUENT based on the FVM(finite volume method). Fresh water generator of this study used Shell & Tubes heat exchanger with Cu_Ni tube, configuration of tube used bare tube and corrugated tube, and arrangement of tube used in-line array and staggered array. Performance of heat exchanger through the formation of liquid film was compared and analyzed. Liquid film flow occurred that falling on heat exchanger tube wall. Result of simulation showed that liquid film thickness of in-line arrangement was found 0.57mm with bare tube and 0.67mm with corrugated tube, respectively. And liquid film thickness of staggered arrangement was found 0.39mm with bare tubes and 0.62mm with corrugated tubes, respectively. Liquid film thickness of corrugated tube showed thicker than bare tube, but heat transfer rates of corrugated tube showed higher than bare tube. The reason was considered that surface area of corrugated tube was wider than bare tube. And liquid film thickness of staggered arrangement showed thinner than in-line arrangement, so thermal performance of staggered arrangement showed higher than in-line arrangement.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.529-534
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• 2023

Although line printing technology is capable of high-speed and large area printing, residual stresses generated during the manufacturing process can deform the feedhole, causing nozzle plate crack or ink leaks. Therefore, in this paper, we propose a new thermal inkjet print head that is robust, reliable and more suitable for line-printing. The amount of deformation of the conventional line printing head measured through the experiment was converted into an equivalent load, and the validity of the load estimation method was verified through FEA analysis. In addition, in order to minimize deformation without increasing the head size, the head structure was designed to increase internal rigidity by reinforcing the unit nozzle with a pillar or support wall or by adding a support beam or dry/wet etched bridge. The FEA analysis results show that the feedhole deformation was reduced by up to 90%, and it is confirmed that the suggested print head with dry etched feedhole bridge operates normally without nozzle plate cracks and ink leakage through fabrication.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.500-507
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• 2002

By this study, on-line real-time radiometric system was developed using a 64 channels linear array of solid state detectors to measure wall thickness of insulated piping system. This system uses an Ir-192 as a gamma ray source and detector is composed of BGO scintillator and photodiode. Ir-192 gamma ray source and linear detector array mounted on a computer controlled robotic crawler. The Ir-192 gamma ray source is located on one side of the piping components and the detector array on the other side. The individual detectors of the detector array measure the intensity of the gamma rays after passing through the walls and the insulation of the piping component under measurement. The output of the detector array is amplified by amplifier and transmitted to the computer through cable. This system collects and analyses the data from the detector array in real-time as the crawler travels over the piping system. The maximum measurable length of pipe is 120cm/min. in the case of 1mm scanning interval.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.231-239
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• 2019

In sonar systems, the passive ranging of a target is an active research area. This paper analyzed the performance of passive ranging based on an array invariant method for different environmental and sonar parameters. The array invariant developed for source range estimation in shallow water. The advantages of this method are that detailed environmental information is not required, and the real-time ranging is possible since the computational burden is very small. Simulation was performed to verify the algorithm. And this method is applied to sea-going experimental data in 2013 near Jinhae port. This study shows the performance of ranging for source orientation, transmission signal length, and length of a receiver through numerical simulation experiments. Also, the results using nested array and uniform line arrays are compared.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.254-259
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• 2012

This paper presents a closely spaced two-element folded-dipole-driven quasi-Yagi array with low mutual coupling between adjacent elements. The antenna utilizes a T-junction power divider as the feeding network, with an input impedance of $50{\Omega}$. A microstrip-stub is added to the ground plane in the middle of the two elements to improve the mutual coupling characteristics. The folded dipole driver is connected to a $50{\Omega}$ microstrip line via a broadband microstrip-to-coplanar stripline transition with a quarter radial stub. A mutual coupling of less than -22 dB is measured between two folded-dipole-driven quasi-Yagi antennas with a center-to-center spacing of 30 mm ($0.55{\lambda}_0$ at 5.5 GHz). The proposed quasi-Yagi array yields a measured bandwidth of 4.75~6.43 GHz for the -10 dB reflection coefficient and a gain of 6.14~7.12 dBi within the bandwidth range.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.200-205
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• 2014

In this paper, 5.8GHz band $4{\times}4$ Butler matrix is designed using easily accessible commercial $90^{\circ}$ hybrid coupler and semirigid coaxial cable as a transmission line. This Butler matrix is very flexible to changes of antenna system specification like a frequency band because $90^{\circ}$ hybrid coupler changing is all to do. The result of design is the distance of $2{\times}2$ array antenna element is $\sqrt{2}{\lambda}/4$, the 4 beam directions are diagonal of array antenna and phase shifter is not necessary. The beam width is roughly $25^{\circ}$ narrower because of array antenna geometry and the side lobe is about 10dB higher partially than theoretical beam pattern. But the overall beam pattern is similar with theoretical beam. This Butler matrix can be applied to switching beam antenna of 5.8GHz band Wi-Fi and WAVE system.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1364-1366
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• 1998

An active-matrix LCD using thin film transistors (TFT) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the gate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the resistivity of gate line material on the pixel operations can be effectively analyzed. The gate signal delay. pixel charging ratio, level-shift of the pixel voltage were simulated with varying the parameters. The information obtained from this study could be utilized to design the larger area and finer image quality panel.