• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.523-526
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• 2002

We designed wideband HTS antennas which consists of two triangle-radiation patches using a YBa$_2$Cu$_3$O$\sub$7-x/ (YBCO) superconducting thin film. The major limitation of high-Tc superconducting (HTS) microstrip antennas is the narrow bandwidth due to the high Q and thin substrate. Defining bandwidth as the frequency range over which standing wave ratio (SWR) 2:1 or less, HTS antenna bandwidths are typically 0.85% to 1.1%. Thus considerable effort has been focused on developing antennas for broadband operation. To calculate input impedance and design of the broadband HTS antennas a moment method technique was used. The HTS antenna fabricated in this work was designed for K-band, which is useful band for satellite-to-satellite communications. The bandwidth obtained was a significant 6.7% and the other measured performance of our HTS antenna, including the bandwidth, radiation Pattern, efficiency, standing wave ratio (SWR) and return losses was reported.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.1
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• pp.41-46
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• 2004

In this paper, we present a new combined field integral equation (CFIE) formulation for the analysis of electromagnetic scattering from arbitrarily shaped three-dimensional perfectly conducting and piecewise homogeneous dielectric composite body. The conducting/dielectric structures are approximated by planar triangular patches, which have the ability to conform to any geometrical surface. The surface covering the conducting body is replaced by an equivalent surface electric current and the surface of the dielectric by equivalent electric and magnetic currents. The all equivalent currents are approximated in terms of RWG (Rao, Wilton, Glisson) functions. The objective of this paper is to illustrate that the CFIE is a valid methodology in removing defects, which occur at a frequency corresponding to an internal resonance of the structure. Numerical results are presented and compared with solutions obtained using other formulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.834-842
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• 2002

The method of moment is applied to the analysis of electromagnetic scattering from an arbitrarily-shaped conductor. The conducting surface is discretized into triangular patches using a GID tool. Surface currents on a conductor are expanded with a vector triangle basis function. By using the Duffy's method, the singular integration appeared in a triangle patch can be transformed into the non-singular integral form suitable for one dimensional Gaussian quadrature integration method. Mutual and self integration extracted singular terms are evaluated by two dimensional Gaussian quadrature techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.177-184
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• 2018

In this paper, we analyze the characteristics of the antenna by changing the structure of the radiator and the angle of the branch of the array patch antenna. First, the structure of the radiator was changed from the rectangular patch to a hexagonal patch, a triangular patch. Secondly, we changed the angle of the feeder branch to $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$. When the branch angle is $10^{\circ}$, the measured 10dB frequency band is 23.38 GHz-24.19GHz and the bandwidth is 810MHz. The fabricated antenna has a gain of 9.65-10.06dBi at 24.05 GHz. The beam width of the main lobe is $12^{\circ}$, and the antenna size is $70{\times}36mm^2$. In addition to the rectangular patch, it is possible to maintain the performance by using patches of other shapes, and it is confirmed that by changing the feeder branch at various angles, it is possible to reduce the substrate size and contribute to diversity in the fabrication of the array antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.510-515
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• 2011

In this paper, an artificial transmission line coupler with slotted-triangular patches, which is compact and spacesaving structure, is proposed. The proposed structure has specific features of not only convenience for adjusting the characteristic impedance and the phase of its coupled line by varying the lengths of the slots of the artificial transmission lines in designing a coupler but also the maximized coupling value at less than ${\lambda}$/4 electrical length so that it can be designed in compact and small dimensions, while conventional coupled line couplers are generally limited in compact and miniaturized designs by their ${\lambda}$/4 transmission lines. A fabricated 15 dB test-coupler at 2.4 GHz band by proposed design method shows good agreement with theory and simulation.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.1 s.149
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• pp.157-166
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• 2006

The human body, which is composed of concave and convex curvatures, makes it difficult to transfer into 2D patterns directly from 3D data. In previous studies. Jeong, et al.(2004) suggested the block method was fester and easier when dealing with the triangular patches of male's upper dress form. Although the block method is useful to make a pattern, the information(area, length, etc.) from a 2D pattern would be different depending on the direction of the block method. As a result horizontal and diagonal block methods were suggested as optimal methods for 2D tight-fitting patterns. These block methods were closer to the original area of the 3D scan data than the vertical block method. The total area of the 2D pattern obtained by the horizontal and diagonal block methods showed little differences. In case of the horizontal and diagonal block methods, the total error of the 2D pattern area ranged from $0.01\%\~0.25\%$. In comparing the length of the 2D pattern with that of the 3D scan data, the obtained 2D pattern was $0.1\~0.2cm$ shorter than the 3D scan data, which was within the acceptable range of errors in making clothes. 3D space distribution images between the body surface and the experimental clothing were also measured and $3\%$ enlargement of the original pattern was verified as the adequate adjustment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.768-773
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• 2012

A branch-line hybrid using microstrip artificial transmission lines(ATLs) with slotted-triangular patches is proposed. The proposed artificial transmission line is compact in structure as well as easy to adjust the characteristic impedance and electrical length of equivalent transmission line by changing the slot's parameters; hence, it is useful for miniaturizing conventional transmission lines. The designed branch-line hybrid, because of the use of the right angled isosceles triangular shaped artificial transmission lines as building blocks, has no useless empty space, and hence optimally miniaturized. A fabricated 3 dB branch-line hybrid shows the coupling variation of ${\pm}0.5$ dB and the phase difference between two output ports of $91^{\circ}{\pm}4^{\circ}$ within 15 % bandwidth at 2.45 GHz center frequency. The size of proposed branch-line hybrid is only 38% of the conventional branch-line hybrid.

• Journal of the Korean Society of Costume
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• v.55 no.2 s.92
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• pp.82-91
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• 2005

The purpose of this study is to analyze the style of trousers of Koguryo(高句麗). Trousers of Koguryo were called Go(袴: trousers) and those had various forms according to the shape of gusset(dang, 糖), width and length of the trousers. Commonly the trousers that had worn by Koguryo people had gausset in those bottom not to be shown hip. The gausset was cut triangle or square so if a person wear the trouser with the triangular gausset, the trouser has a pointed hip. Sometimes the trousers had non pointed hips were dicovered in the wall-paintings of the Koguryo tombs, they are thought the trousers that had no gaussets or square one. And also there were another trousers that had wide/narrow legs and long/short legs. Trousers of wide legs were called Gwango(寬袴) and narrow legs Sego(細袴). Gwango(寬袴) grew wider over time and in the late age, the trousers were called Daegugo(大口袴) with wide ends were worn. Trousers were also decorated elaborately with patches on the edges, leg ties, vents, etc.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.95-107
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• 1999

The design models of a new product in general are created using clay models or wooden mock-ups. The reverse engineering(RE) technology enables us to quickly create the CAD model of the new product by capturing the surface of the model using laser digitizers or coordinate measuring machines. Rapid prototyping (RP) is another technology that can reduce the product development time by fabricating the physical prototype of a part using a layered manufacturing technique. In reverse engineering process, however, the digitizer generates an enormous amount of point data, and it is time consuming and also inefficient to create surfaces out of these data. In addition, the surfacing operation takes a great deal of time and skill and becomes a bottleneck. In rapid prototyping, a faceted model called STL file has been the industry standard for providing the CAD input to RP machines. It approximates the CAD model of a part using many planar triangular patches and has drawbacks. A novel procedure that overcomes these problems and integrates RE with RP is proposed. Algorithms that drastically reduce the point clouds data have been developed. These methods will facilitate the use of reverse engineered geometric data for rapid prototyping, and thereby will contribute in reducing the product development time.

• Journal of the Korea Computer Industry Society
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• v.2 no.3
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• pp.297-308
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• 2001

We propose an algorithm which can reconstruct the 3D information from geographical information. The conventional techniques, the triangular patches and the Random Fractal Midpoint Displacement (RFMD) method, etc., have often been used to reconstruct natural images. While the RFMD method using Gaussian distribution obtains good results for the symmetric images, it is not reliable on asymmetric images immanent in the nature. Our proposed algorithm employs neural networks for the RFMD method to present the asymmetrical images. By using a neural network for reconstructing the 3D images, we can utilize statistical characteristics of irregular data. We show that our algorithm has a better performance than others by the point of view on the similarity evaluation. And, it seems that our method is more efficient for the mountainous topography which is more rough and irregular.