• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.4
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• pp.53-63
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• 2013

The purpose of this study is to analyze impacts of the forest fragmentation caused by development project. Furthermore, to investigate the applicability of landscape indicator when 'Feasibility of forest land conversion to other use' is conducted. The study site was consisted of golf course development and road construction. It is to compare before and after impacts of areal and linear development. As for the methods, selecting landscape indices, clustered into 3 Categories have been utilized. Category I was concerned with 'size of forest patches', II as 'shape of forest patches', and III as 'Core Area' These were calculated by FRAGSTATS, the program for analyzing fragmentation. The results showed that linear development caused more fragmented than areal development projects. Also, patch size, patch shape and core area are related to impacts of development, while Patch size decreased, patch shape and core area increased after development. Therefore, it is necessary to minimize the impacts of forest by considering fragmentation when development project is planned.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.4
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• pp.198-205
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• 2005

In this paper, the miniaturization of aperture-coupled RHCP patch antenna for the GPS system is treated. Circularly polarization characteristics is implemented by truncating diagonal corners of the square patch. Antenna size is reduced by inserting four uniform slits at the patch edges, which was equivalently lengthened the surface current by meandering it, This antenna uses aperture-coupled feeding structure with crossed-slot shape in order to give easy miniaturization of RHCP patch antenna. Simulated and measured results show that $42.7\%$ lower antenna size is obtained, and also $56\%$ lower -10dB bandwidth and $38.5\%$ lower 3dB AR bandwidth are obtained. when the proposed design scheme is applied to a commercial GPS antenna structure, $42.9\%$ lower patch size and $56\%$ lower 3dB AR bandwidth compared to commercial antenna at the same frequency are obtained.

• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.122-125
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• 2005

This paper describes a design of a miniature patch antenna and its 4-channle array for 5.25 GHz wireless LAN band. Each patch element is designed for the low mutual coupling between each element and for the small size of the array antenna. The size of the each element is $7 mm{\times}14.5 mm{\times}5.6 mm$ and it satisfy IEEE 802.11a frequency band. It is arrayed for independent 4-channel operation. The total size of the array antenna is $35.6 mm{\times}52.5 mm{\times}5.6 mm$. The measured reflection coefficients and the radiation patterns of the fabricated antennas show the reasonable agreements with prediction.

• ETRI Journal
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• v.30 no.4
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• pp.600-602
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• 2008

A very small patch-type RFID tag antenna (UHF band) using ceramic material mountable on metallic surfaces is presented. The size of the proposed tag is 25 mm${\times}$25 mm${\times}$3 mm. The impedance of the antenna can be easily matched to the tag chip impedance by adjusting the size of the shorting plate of the patch and the size of the feeding loop. The measured maximum reading distance of the tag at 910 MHz was 5 m when it was mounted on a 400 mm${\times}$400 mm metallic surface. The proposed design is verified by simulation and measurements which show good agreement.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.492-495
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• 2003

This paper presents a novel method to reduce the size of microstrip patch antennas using shorting post and spiral shape. The spiral conductor shape of the proposed shorted patch antennas increases the length of the current patch for a given area. Two spiral shaped patch antennas with shorting post operating at 700 MHz bands are investigated experimentally.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.169-175
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• 2006

In this paper, a microstrip patch antenna with the T-shaped slits is designed and fabricated for GPS. The resonant frequency of the microstrip patch antenna with the slits is lower than that of a microstrip patch antenna without the slits so it can be reduced the size of patch. In order to calculate resonant frequency of the microstrip patch antenna with the slits, the resonant frequency formulas are derived from the surface current distribution on microstrip patch antenna. Using the Ensemble 6.0 simulation tool, the accuracy of approximate equations is verified. The microstrip patch antenna with the slits is designed by using these equations. The size of the designed antenna with T-shaped slits can be reduced to 29% compared with that without the slits. The microstrip patch antenna with slits have a very narrow bandwidth. In order to improve the narrow bandwidth of microstrip patch antennas with the slits, a microstrip patch antenna with rectangular slot is proposed. As the result of the measurements, the resonant frequency of the proposed microstrip patch antenna with the T-shaped slits is 1.575GHz and the bandwidth is about 50MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.920-928
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• 2000

In this paper, using newly proposed size reduction technique, the aperture coupled microstrip patch antenna for a repeater system in a mobile communication cellular band (824~849 MHz) is developed with a wide bandwidth, small size, light weight, and low cost. The resonant frequency of microstrip antennas is related to the electric field distribution of the radiating patch. The field strength of $TM_{01}$ mode of a rectangular patch antenna is strongest at each of the extremities of the radiating patch, but negligible at center. Therefore, the size of a patch antenna can be effectively minimized by inserting the narrow rectangular dielectric into just under the edges of the resonant Patch. This Paper also proposes the bandwidth improvement technique by using under-coupling technique with a tuning stub. The VSWR is less than 1.5 : 1 for the whole cellular band. The simulation tool was HFSS, Agilent Technologies, Inc.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.2
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• pp.55-60
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• 2000

A comparison of Riveted and bonded repairs, bearing and net tension failures, and Al 6061-T6 plates is presented. The results are then compared with previous papers about bonded repairs on different patch materials and shapes. Aluminum alloys, including Al 6061-T6, have a face-centered-cubic crystal structure. Under normal circumstances, these types of crystal structures do not exhibit cleavage fractures even at very low temperatures. In aluminum-base structures, the cracked plate structures are frequently repaired using mechanical fasteners-either rivets of bolts- even though patch-bonding techniques are applied to repair and reinforce the structure. Static test results indicate that the riveted repairs are affected by the position of the rivers. When using the same size of patch, the bonded repair technique is stronger; the rate of elongation is also increased. Form FEM analysis, it is revealed the origin of patch debonding in patch-bonded structures is the edge of the patch along to the tensile strength.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.183-186
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• 2002

In this paper, a microstrip Patch antenna with the T-shaped slits, which are employed to reduce the patch size. is proposed for GPS In order to analyze characteristics of the antennas are defined green function of the moment method. The microstrip Patch antenna and microstrip Patch with the T-shaped slits are fabricated. The numerical result of return loss and -10d13 bandwidth are compared with measured results.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.204-209
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• 2005

A small size broadband microstrip patch antenna with small ground plane has been fabricated using MEMS. Multiple layer substrates are used to realize small size and broadband characteristics. The microstrip patch is divided into 3 pieces and each patch is connected to each other using a metal microstrip line. The fabrication process is simple and only one mask is needed. Two types of microtrip antennas are fabricated. Type A is the micros trip antenna with metal lines and type B is the microstrip antenna without metal lines. The size of proposed microstip antenna is $8^{*}12^{*}2mm^{3}$ and the experimental results show that the antenna type A and type B have the bandwidth of 420 MHz at 5.3 GHz and 480 MHz at 5.66 GHz, respectively.