• The Journal of the Convergence on Culture Technology
• /
• v.6 no.2
• /
• pp.467-472
• /
• 2020

Methods for deriving design input-parameters to ensure the stability of a structure on a common ground are generally well known. Folded metamorphic rocks, such as the study area, are highly foliated and have small faults parallel to the foliation, resulting in special research methods and tests to derive design input parameters, Etc. are required. The metamorphic rock ground with foliation development of several mm intervals has a direct shear test on the foliation surface, the strike/dip mapping of the foliation, the boring investigation to determine the continuity of the foliation, and the rock mass rating of the metamorphic rock. etc. are required. In the case of a large number of small foliation-parallel faults developed along a specific foliation plane, it is essential to analyze the lineament, surface geologic mapping for fault tracing, and direct shear test. Folded ground requires additional geological-structural-domain analysis, discontinuity analysis of stereonet, electrical resistivity exploration along the fold axis, and so on.

• Journal of IKEEE
• /
• v.20 no.1
• /
• pp.68-74
• /
• 2016

In this paper, we present a compact planar dual band rejection Ultra Wide Band(UWB) antenna with folded parasitic element. The proposed antenna is consist of a hexagonal planar radiation patch antenna with a folded parasitic element which is located over the top and bottom surface. In contrast with other antenna which rejects single band using one method, folded parasitic element rejects dual band using one simple structure. Owing to folded parasitic element, dual-rejected properties are achieved in the Worldwide Interoperability for Microwave Access(WiMAX), C-band, and Wireless Local Area Network(WLAN) bands. The bandwidth of the proposed antenna was measured as 3.1~10.6 GHz for voltage standing wave ratio(VSWR) less than 2, except for the dual rejection bands of 3.4~4.2 GHz and 5.15~6.00 GHz.

• Journal of Advanced Navigation Technology
• /
• v.17 no.5
• /
• pp.491-496
• /
• 2013

In this paper, a half-wavelength folded-slot antenna, which can be applied to RF module for 3G mobile communications by which security lights are monitored and controlled, is proposed. The proposed antenna can be regarded as modified folded-slot structure which has the size reduced to a half of conventional ${\lambda}g$ folded-slot antenna and can be placed at the ground plane edge. In spite of that, the proposed antenna still maintain the advantage of conventional folded-slot antenna that input impedance is close to $50{\Omega}$. The antenna is designed and fabricated within the upper space of $40.5{\times}10mm^2$ on $40.5{\times}62mm^2$ substrate for 3G mobile communication frequency band. The measured impedance bandwidth and antenna gain are 390 MHz and 2 dBi respectively.

• Steel and Composite Structures
• /
• v.46 no.3
• /
• pp.319-334
• /
• 2023

Localizing damages is an essential task to monitor the health of the structures since they may not be able to operate anymore. Among the damage detection techniques, non-destructive methods are considerably more preferred than destructive methods since damage can be located without affecting the structural integrity. However, these methods have several drawbacks in terms of detecting abilities, time consumption, cost, and hardware or software requirements. Employing artificial intelligence techniques could overcome such issues and could provide a powerful damage detection model if the technique is utilized correctly. In this study, the crack localization in flat and folded plate structures has been conducted by employing a Backpropagated Artificial Neural Network (BPANN). For this purpose, cracks with 18 different dimensions in thin, flat, and folded structures having 15⁰, 30⁰, 45⁰, and 60⁰ folding angle have been modeled and subjected to free vibration analysis by employing the Classical Plate Theory with Finite Element Method. A Four-nodded quadrilateral element having six degrees of freedom has been considered to represent those structures mathematically. The first ten natural frequencies have been obtained regarding healthy and cracked structures. To localize the crack, the ratios of the frequencies of the cracked flat and folded structures to those of healthy ones have been taken into account. Those ratios have been given to BPANN as the input variables, while the crack locations have been considered as the output variables. A total of 500 crack locations have been regarded within the dataset obtained from the results of the free vibration analysis. To build the best intelligent model, a feature search has been conducted for BAPNN regarding activation function, the number of hidden layers, and the number of hidden neurons. Regarding the analysis results, it is concluded that the BPANN is able to localize the cracks with an average accuracy of 95.12%.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.1
• /
• pp.19-24
• /
• 2024

In this paper, in order to realize lower cut-off frequency of the waveguide, the folded Ridge waveguide (FRWG) is suggested by alternating T-shape structure in the conventional folded waveguide with Y-shape structure. Suggested FRWG can be equivalent by the reverse Ridge waveguide. As the height of side of the FRWG is lower, the width of side is increased. Therefore, the cut-off frequency of the FRWG can be decreased more than half compared with conventional waveguide. The FRWG is designed with the length, height, and width of Y-shape structure of 40mm, 20mm, and 2mm, respectively. Designed FRWG has the cut-off frequency of the 1.996GHz. Also, the transition between the FRWG and SMA connector is designed. The transition is optimized by the capacitance of the signal line of the connector. Its result shows the VSWR under 2:1 in the band of 2.064 ~ 3.050 GHz. Suggested FRWG can be applied with miniaturization of various waveguide devices.

• Journal of electromagnetic engineering and science
• /
• v.14 no.1
• /
• pp.31-35
• /
• 2014

An ultra-wideband (UWB) circular monopole antenna with a multiband-notched characteristic is proposed. The multiband-notched filter consists of three different sized folded slots, which are distinctly assigned for the notched band at the 3.5-GHz WiMAX, 5-GHz WLAN, and 8-GHz ITU bands. The proposed antenna results in a measured ${\mid}S_{11}{\mid}$ < -10 dB, which completely covers the UWB band (3.1 10.6 GHz) with three notched bands at 3.5, 5.5, and 8.0 GHz. The antenna yields an omnidirectional radiation pattern and high radiation efficiency.

• Journal of electromagnetic engineering and science
• /
• v.10 no.2
• /
• pp.67-72
• /
• 2010

A new type of monopole antenna whit broadband characteristics is presented in this article. To reduce the size of the antenna, its upper part is folded. By separating the current flow, the resonance in the shorter part is in the higher band; and the longer part resonates in the lower band. This gives the broadband characteristics of the antenna. Slots on the corner using an oblique line improve the impedance matching and bandwidth. The measurement results show that the bandwidth operates from 0.848~0.992 GHz and 1.744~2.528 GHz, and the radiation patterns are in an omni-directional shape.

• Journal of the korean Society of Automotive Engineers
• /
• v.7 no.3
• /
• pp.42-55
• /
• 1985

The study is concerned with the investigation of curved line folding of developable surface from flat sheets of metal. General geometric relations among folding line, folded surface, folded angle are derived. From the derived geometric relations, the required plastic work and punch force are derived for the first approximation. Five methods of forming are suggested and the experiment is carried out using two chosen methods for the prismatic developable surfaces of which cross-sections have 103.deg.arc, 180.deg.arc, sinusoidal shape. In the die design for the tolding of prismatic developable surfaces, a stack of sheets were used to form shapes of the dies by which acceptable folded surfaces were obtained. The computed plastic work and punch force turned out to be in reasonable agreement with the experimental result.

• Journal of information and communication convergence engineering
• /
• v.8 no.5
• /
• pp.489-492
• /
• 2010

This paper proposes the planar-type modified monopole antennas of loop structure. This antenna has an opened center of a conventional closed loop structure with an inside-folded terminal of the loop microstrip line. The size of the proposed antenna was minimized by folding the end of the loop. Also, the reactance value has been minimized by increasing capacitances between the coupled microstrip line. Therefore the proposed antenna has been compacted to about 20% from a conventional loop antenna and has increased its efficiency. The proposed antennas have an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6~3.56 GHz) with VSWR$\leq$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9%. These properties could satisfy the S-DMB band.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.265-268
• /
• 2003

In this paper, we introduce the SIR typed bandpass filters in CPW structures for shifting spurious harmonic frequency into higher frequency band. And we proposed the effective feed structures for suppressing spurious frequency in the SIR typed CPW bandpass filters. The designed folded feed structures have lowpass filtering characteristic. They are very effective feed types in the CPW bandpass filters for suppressing harmonics. The measured results of the CPW bandpass filter with folded feed line shows that it has suppressed and wide out-of-band up to 5.8fo.