• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.402-409
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• 2005

In analog and digital electronic systems, crosstalk between transmission lines on the printed circuit board can degrade the performance of equipment operations. This paper presents a technique to analyze the effects of via fence, which is based on additional transmission lines grounded by vias. The technique is composed of a circuit concept approach for transmission line sections md an impedance modeling of via hole sections. All sections are represented by ABCD parameters and they are cascaded. Finally, this technique was verified by comparing the measurement results with the simulation ones.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.408-411
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• 2008

In an attempt to enhance luminance efficiency and to reduce discharge delays of test panels with aluminum fence-electrodes, various designs of the electrodes were prepared by chemically etching the aluminum foils bonded to soda-lime glass substrate via anodic bonding process. The effects of fence design on luminance and discharge characteristics were investigated and compared with conventional ac-PDPs. These results showed a possibility of using fence-type aluminum electrode at front plates of ac-PDDs without sacrificing its performance.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.169-175
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• 2007

In High-Speed DSP systems, crosstalk between transmission lines of multi-channel can degrade the performance of equipment operations. This paper presents a microwave board to measure multi-channel coaxial cable assembly. The designed board has good performances from DC to 3 GHz, which have improved characteristic impedance, reduced crosstalk by using via fence, and low transmission loss. Using the designed board, we can measure characteristics of DUT(Device Under Test) such as return loss, insertion loss, crosstalk phase delay, and characteristic impedance. The measured results are used to improve performances of a produced coaxial cable assembly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.73-80
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• 2004

In this paper, the implementation and embedding method of the existing air-filled waveguide-filters at millimeter-wave on general PCB substrate is introduced by systematically inserting the vias inside waveguide and mathematically manipulating the simple equations obtained ken the classical circular-post waveguide filter design. All the metal structures placed vertically such as side wall fur perfect ground plane and circular-post for signal control in the air-filled WR-22 waveguide are replaced with several types of via for constructing the bandpass-filter. Side wall and poles inside waveguide are realized by placing a series array of via and tuning the via diameter. The lengths of x, y, z axis are reduced in proportion to root square of employed substrate dielectric constant and especially the length of z axis can be more reduced due to the characteristics of the wave propagation. Because the mass production on PCB is possible without fabricating a large-scaled metal waveguide of WR-22 as input/output ports at millimeter-wave regime, the manufacturing cost is reduced considerably. Finally, when using multilayer process like LTCC for small-sized module, it is one of advantages to use only one layer f3r the filter fabrication. To evaluate the validity of this novel technique, order-3 Chebyshev BPF(Bandpass-Filter) centered at 40 GHz-band with a 2.5 ％ FBW (Fractional Bandwidth) were used. The employed substrate has relative dielectric constant of 2.2 and thickness of 10 mil of Rogers RT/Duroid 5880. Accroding to design and measurement results, a good performance of insertion loss of 2 ㏈ and return loss of -30 ㏈ is achieved at full input/output ports.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.1036-1042
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• 2005

The crosstalk between bent transmission lines and the effects of additional trace with the metal filled via holes on alleviating the crosstalk are investigated using the circuit concept approach for transmission line sections and impedance modeling for via hole sections. All sections are represented by ABCD matrices and then cascaded. Finally the calculated results by proposed method are confirmed that they agree with the measured results in less than 3 dB except a band of low frequency.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.173-181
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• 2016

Several falling-sensing terminals have been developed which are able to detect the fall/upset accident of the elderly and transmit the collapsing signals to the administrative server via RF communication using 400MHz bandwidth. Supposing there might be no communication problem within a sanatorium, just single terminal without relay function had been made as a prototype in the first stage of development. However some communication problems have discovered at the coner of the floor apart from the other floor diagonally in the same building. Same kind of problems have been happened in the area behind a steel fence or a car. To solve these kinds of communication problems, we have developed several terminals and added up relay function to them. In this paper we represented that the success ratio of the communication has been improved by using relay function among several terminals.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.457-465
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• 2013

We integrated and correlated datasets from surface and subsurface geophysics, drilling cores, and engineering geology to identify geological interfaces and characterize the joints and fracture zones within the rock mass. The regional geometry of a geologically weak zone was investigated via a fence projection of electrical resistivity data and a borehole image-processing system. Subsurface discontinuities and intensive fracture zones within the rock mass are delineated by cross-hole seismic tomography and analyses of dip directions in rose diagrams. The dynamic elastic modulus is studied in terms of the P-wave velocity and Poisson's ratio. Subsurface discontinuities, which are conventionally identified using the N value and from core samples, can now be identified from anomalous reflection coefficients (i.e., acoustic impedance contrast) calculated using a pair of well logs, comprising seismic velocity from suspension-PS logging and density from logging. Intensive fracture zones identified in the synthetic seismogram are matched to core loss zones in the drilling core data and to a high concentration of joints in the borehole imaging system. The upper boundaries of fracture zones are correlated to strongly negative amplitude in the synthetic trace, which is constructed by convolution of the optimal Ricker wavelet with a reflection coefficient. The standard deviations of dynamic elastic moduli are higher for fracture zones than for acompact rock mass, due to the wide range of velocities resulting from the large numbers of joints and fractures within the zone.