• Current Optics and Photonics
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• v.5 no.1
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• pp.8-15
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• 2021

An elliptical zone plate (EZP) array is important in off-axis optical systems because it provides two advantages. First, the residual beam and the main source are not focused in the same direction and second, the light from the observation plane is not reflected back towards the beam source. However, the fill factor of the previous EZP array was about 76% which was a little low. Hence, this EZP array could not collect the maximum amount of illumination light, which affected the overall optical performance of the lens array. In this study, we propose a new EZP array design with a 97.5% fill factor used in off-axis imaging system for enhancement of brightness and contrast. Then, direct laser lithography was used to fabricate the high fill factor EZP array by moving the XY linear stage of the system in a zigzag motion. The imaging properties of the proposed EZP array were experimentally verified at the focal plane and compared with the previous model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.120-123
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• 1999

This paper presents the design method of EMC(Electromagnetic Coupling) microstrip array antenna for CS(Communication Satellite) system. Microstrip dipole antennas are attractive elements owing to the desirable properties such as simplicity, small size and linear polarization. From the optimum simulation results by the FDTD method[1], design parameters such as EMC dipole length, width, height and offset are discussed at 12CHz. The array characteristics of 5-elements and 10-elements array are also presented. By adjusting geometry of model antenna, we can design dual polarization EMC microstrip dipole antenna for CS system. Direction of nam beam is easily tilted by the control of distance between dipole elements.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.15-21
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• 2017

In the active SONAR system, various studies have been carried out to enhance the resolution of a received signal. In order to obtain higher resolution for detecting a bottoming cylindrical object, the design of a planar array for SONAR is investigated in this paper. It is necessary to employ planar structures for SONAR array to obtain narrower beam pattern which gives high resolution. In this study, the transmit frequency of each acoustic transducer, which consists of an array is 13 kHz. For efficient detection of a target of an asymmetric size, the concept of areal angle is applied, which considers resolution according to both azimuth and elevation angles in array design. In the design, the areal angle is first investigated to satisfy the resolution requirements, and then based on the value of areal angles, the azimuth angle and the elevation angle are calculated respectively to design an array.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1606-1616
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• 1989

In this paper, the design of DYNAMIC CMOS ARRAY LOGIC which has both advantages of dynamic CMOS and array logic circuits is proposed. The major components of DYNAMIC CMOS ARRAY LOGIC are two-stage dunamic CMOS circuits and an internal clock generator. The function block of dynamic CMOS circuits is realized as a parallel interconnection of NMOS transistors. Therefore the operating speed of DYNAMIC CMOS ARRAY LOGIC is much faster than the one of the conventional dynamic CMOS PLAs and static CMOS PLA. Also, the charge redistribution problem by internl delay is solved. The internal clock generator generates four internal clocks that drive all the dynamic CMOS circuits. During evaluation, two clocks of them are delayed as compared with others. Therefore the race problem is completoly eliminated. The internal clock generator also prevents the reduction of circuit output voltage and noise margin due to leakage current and charge coupling without any penalty in circuit operating speed or chip area utilization.

• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.129-138
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• 1996

This paper describes design techniques of general purpose thermal array printer, especially easily applicable to medical measurement equipment. The'general'means that the proposed thermal array printer can be applied to not only medical field but other industrial field by establishing the eligible protocol. The thermal array printer is composed of i)MPU and its peripherals ii)printer head control, iii)diverse protection circuits, and iv)serial communication. In this paper the performance of the proposed thermal array printer was evaluated by applying to an 3 channel electrocardiogram recorder. The propped system can support'Hangul'text as well as alphanumeric characters and any bitmap image.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.49-63
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• 2017

Solar cells have widely been utilized for a satellite to convert sunlight energy into electricity in space. Many different types of solar cells appropriate for each satellite program are available in current markets, which enables us to construct a solar array light and small often required from a low Earth orbit (LEO) synthetic aperture radar (SAR) satellite. Thus, it is important to choose a proper solar cell satisfying the requirements of mass and size for the solar array. In this article, we have surveyed typical suppliers and have discussed some characteristics of solar cells. Conceptual design examples of the solar array for LEO SAR satellites using several types of solar cells have been performed to show the pros and cons of solar cells by comparison of the total mass and size necessary for the solar array.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.112-118
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• 2013

Formula race car is generally recognized as a vehicle which is optimally designed for on-road race track with the regulations of race host bodies. Especially, the uprights of suspension system decisively have effects on the performance of cornering and stability of race car's driving performance, which are very important factors in the design of race car. This paper is a study of optimal upright design of F1800 grade formula race car which are normally used in professional race circuit in Korea. To design optimally the front upright of F1800 formula race car, Taguchi's orthogonal array, which is known for more useful method than full factorial design experimental method in cost and time, is used with CAE method such as FEM analysis. And the result of this paper shows that Taguchi's orthogonal array employed for this optimal design is very useful for designing the front upright of race car by minimizing its weight as well as keeping its safety factor as enough as designer wants in the view of quality, cost and delivery at the early design step.

• The Journal of the Acoustical Society of Korea
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• v.31 no.1
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• pp.51-61
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• 2012

In this research, we have analyzed the trend of radiation pattern variation in relation to the change of design variables such as source interval and source number for conformal array transducers arranged in equi-angle, equi-interval, and geodesic dome forms. Through statistical multiple regression analysis of the results, we derived functional forms of the side lobe level and the beamwidth in terms of the design variables. Futhermore, the structure of the array transducer was optimized to achieve the smallest side lobe level while satisfying the requirements on beam width by the GA (genetic algorithm) method. Based on the optimized results, we have determined the equi-interval form as the optimal array geometry among the three conformal array geometries.

• Advances in Computational Design
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• v.8 no.4
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• pp.273-293
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• 2023

This study evaluated the acoustic performance of two configurations of serial HR arrays and lined HR arrays in the presence of grazing flow using a 3D numerical simulation. The dual, triple, and quad HR arrays were compared to the conventional HR array. The simulation results showed that the number of resonant frequencies increased with the number of serial HR arrays. The C_TL did not significantly change with the number of serial HR arrays. The acoustic performance of the two, three, and four-lined HR arrays was compared to the conventional HR array. The results showed that the resonant frequency and TLmax increased with the number of lined HR arrays. The C_TL also increased with the number of lined HR arrays. The effect of the grazing flow Mach number (M_a) was investigated on the four-lined HR array configuration and compared to the conventional HR configuration. TLmax and C_TL decreased for both configurations with increasing M_a. The four-lined HR array configuration had significantly better acoustic performance than the conventional HR configuration. The TLmax and C_TL increased by more than 300% when the configuration was changed from the conventional HR to the four-lined HR array at M_a = 0.The increment percentage decreased with increasing M_a.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.50-57
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• 2001

This paper describes a design for the circularly polarized microstrip EMC cross dipole array antenna with the wide bandwidth. To realize the characteristics of wide bandwidth and circular polarization, the electromagnetic-coupled cross dipole element is proposed. The optimum design parameters of a circularly polarized EMC cross dipole element are calculated by the FDTD and the Ensemble. To obtain the uniform aperture illumination of electric field in an array, offset technique that the cross dipole elements are alternatively arranged on center of the microstrip feed line is adopted. In 20-element array design, the calculated axial ratio and gain are about 0.1dB and 9.9 dBi at 12 GHz, respectively, The frequency characteristics of a fabricated 20-element array antenna are measured. The calculated results agree well with the measured ones.