• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.22-28
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• 1998

Signal transmission and crosstalk of coupled bondwires buried in plastic packages are analyzed using the Method of Moments and the Fourier Transform algorithm. It is also shown that the quasi-static crosstalk model of SPICE is inappropriate for designing the high-speed plastic packages. Plastic packaging material, increasing the self and mutual capacitances, is found to be helpful for the signal transmission integrity due to the dielectric compensation effect. However, it is also observed that the plastic material increases the crosstalk due to the radiation-enhanced mutual coupling effect. By investigating the geometrical and material dependence of the pulse transmission and crosstalk, it is found that the radiation-enhanced coupling effect is significant for most of typical bondwire geometries and plastic package materials. These calculation results can be effectively used for designing plastic packages of high-speed digital IC's and monolithic RFIC's.

• Environmental Engineering Research
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• v.14 no.2
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• pp.81-87
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• 2009

The decomposition of antibiotics (cefaclor) by gamma irradiation in aqueous solutions was experimentally evaluated. To obtain a mutual interaction between two factors (antibiotics concentrations and radiation doses) and to optimize these factors during the process, experimental design and statistical analysis were employed. The decomposition capability of the gamma radiation was also mathematically described as a function of cefaclor concentration and gamma-ray dose using the statistical analysis. The results showed that the cefaclor concentration ($X_1$) in the response $Y_1$ (Reduction of cefaclor concentration) and gamma-ray dose ($X_2$) in the response $Y_2$ (Removal efficiency (%) of cefaclor concentration) exhibited a significantly positive effect, whereas gamma-ray dose ($X_2$) in the response $Y_1$ showed a significantly negative effect. The estimated ridge of maximum responses and optimal conditions for $Y_1$:($X_1$,$X_2$)=(25 mg/L, 350 Gy) and $Y_2$:($X_1$,$X_2$)=(21 mg/L, 565 Gy) using canonical analysis were 4.37 mg/L of reduction of cefaclor concentration and 98.35% of removal efficiency of cefaclor concentration, respectively. The measurement values agreed well with the predicted ones, thereby confirming the suitability of the model for $Y_1$ and $Y_2$ and the success of the experimental design in optimizing the conditions of the gamma irradiation process.

• Journal of electromagnetic engineering and science
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• v.18 no.3
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• pp.175-181
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• 2018

The array patterns of a patch array antenna were calculated using an active element pattern (AEP) method that considers ground edge effects. The classical equivalent radiation model of the patch antenna, which is characterized by two radiating slots, was adopted, and the AEPs that include mutual coupling were precisely calculated using full-wave simulated S-parameters. To improve the accuracy of the calculation, the edge diffraction of a ground plane was incorporated into AEP using the uniform geometrical theory of diffraction. The array patterns were then calculated on the basis of the computed AEPs. The array patterns obtained through the conventional AEP approach and the AEP method that takes ground edge effects into account were compared with the findings derived through full-wave simulations conducted using a High Frequency Structure Simulator (HFSS) and FEKO software. Results showed that the array patterns calculated using the proposed AEP method are more accurate than those derived using the conventional AEP technique, especially under a small number of array elements or under increased steering angles.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.48-58
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• 2015

The bandwidth enhancement of an aperture coupled microstrip patch antenna(ACMPA) with a high permittivity feed substrate suitable for the integration with MMIC is investigated using variation of an aperture width. As an aperture width increases, the 10 dB return loss bandwidth increases due to the increase of the mutual resonance region between a patch resonance and an aperture resonance. The bandwidth of an ACMPA with extended aperture width is increased up to 35.3 % from 20.8 % of the ACMPA with an aperture of a typical aspect ratio 10:1. The degradation of the radiation characteristics of an ACMPA due to the increase of an aperture width is very small.

• Journal of electromagnetic engineering and science
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• v.12 no.2
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• pp.176-184
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• 2012

In this paper, the effects of a metal plane on the performance of a meandered slot RFID antenna are evaluated in a real environment, and 3 metal plane cases are considered (the most likely scenarios in which metal conductive materials are placed near the tag antenna). The metal plane effects can be categorized as matching degradation and antenna gain variation. First, matching degradation due to the antenna's induced mutual impedance is experimentally investigated. In addition, the gain variation is investigated to figure out the change in the radiation characteristics. With the derived antenna parameters, the read range is calculated with the Friis transmission equation and measured to analyze the effects of a metal plane on RFID system performance. The calculated and measured read range varies from 9.3 m to 19.1 m as the distance between the RFID antenna and the metal plane changes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.620-628
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• 2007

An H-sector horn antenna has a constant beam coverage characteristic and it can be useful for application to a wide band phased array antenna system. In this paper, we designed a broadband E-plane H-sector horn phased-array antenna, which has a 3:1 bandwidth and ${\pm}60^{\circ}$ beam steering capability. An H-sector hem antenna was designed to have $30{\sim}50^{\circ}$ half-power beam width in the principal H-plane. The active reflection coefficient including mutual coupling was calculated using a waveguide simulator, and the active reflection characteristic was improved by mutual coupling over wide frequency range. Using these results, an $8{\times}1$ H-sector phased array antenna was fabricated. The measurement results for the half-power beam width in the principal H-plane and the active reflection coefficient showed a good agreement with the simulation results. The peak-value pattern in the steered radiation beams also agreed well with the active element pattern. The measured active reflection coefficients within the beam steering range are mostly less than 0.3 over the 3:1 frequency range.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.77-83
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• 2010

Radiation characteristics of $5{\times}4$ pin array patch antennas are compared to those of $5{\times}2$ pin array patch antennas for several substrate thicknesses using the computer simulation. Since the number of unit cells of a $5{\times}2$ pin array patch antenna is half of that of a $5{\times}4$ pin array patch antenna, the number of pins used in a $5{\times}2$ pin array patch antenna is half of that in a $5{\times}4$ pin array patch antenna and the patch width of a $5{\times}2$ pin array patch antenna is very small compared to that of a $5{\times}4$ pin array patch antenna. However, the radiation characteristics of a $5{\times}2$ pin array patch antenna are almost similar to those of a $5{\times}4$ pin array patch antenna.

• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.599-606
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• 1998

This study was carried out to develop the control system with PLC and its operating software and to investigate its control ability of greenhouse environments. Two experimental greenhouses were controlled by PLC and ON/OFF controller, respectively. In greenhouse controlled by PLC, target values of air temperature, relative humidity and $CO_2$ concentration were automatically changed. In warm-water heating, the variation of air temperature was reduced to $\pm$ $0.6^{\circ}C$ by the method of proportional-integration(PI) control with an inverter. In ventilation, the variation of air temperature was reduced, since windows open and close with multistage by mutual relation formula among the target, indoor, and outdoor temperature. Relative humidity at daytime was maintained with range of 35% to 55% by PLC controlled fogger. $CO_2$ concentration was automatically controlled from 300 to 800 $\mu$molㆍ$mol^{-1}$ according to amount of solar radiation. The suppling amount and frequency of nutrient solution were controlled by total integrated solar radiation. Difference in the yield of cucumber in the greenhouse controlled by PLC and by ON/OFF controller was not significant at the 5% level.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.323-333
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• 2007

In this paper, a new MDAS-DR antenna structure designed to efficiently shape a flat-topped radiation pattern is proposed. The antenna structure is composed of a stacked micro-strip patch exciter and a multi-layered disk array structure(MDAS) surrounded by a dielectric ring. The MDAS, which was supplied by a stacked microstrip patch exciter with radiating power, can form a flat-topped radiation pattern in a far field by a mutual interaction with the surrounding dielectric ring. Therefore, the design parameters of the dielectric ring and the MDAS structure are important design parameters for shaping a flat-topped radiation pattern. The proposed antenna used twelve multi-layered disk array elements and a Teflon material with a dielectric constant of 2.05. An antenna operated at 10 GHz$(9.6\sim10.4\;GHz)$ was designed in order to verify the effectiveness of the proposed antenna structure. The commercial simulator of CST Microwave $Studio^{TM}$, which was adapted to a 3-D antenna structure analysis, was used for the simulation. The antenna breadboard was also fabricated and its electrical performance was measured in an anechoic antenna chamber. The measured results of the antenna breadboard with a flat-topped radiation pattern were found to be in good agreement with the simulated one. The MDAS-DR antenna gain measured at 10 GHz was 11.18 dBi, and the MDAS-DR antenna was capable of shaping a good flat-topped radiation pattern with a beam-width of about $40^{\circ}$, at least within a fractional bandwidth of 8.0 %.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.167-171
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• 2011

In this paper, $2{\times}4$ microstrip patch antenna are proposed to implement K-band satellite communications. The microstrip feed line are inset into the radiation patch to match input impedance. Also the same current in each elements are excited by Kirchhoff's low. The elements distance of proposed array antenna are optimized $0.8{\lambda}_g$ to minimize a mutual coupling and maximize a gain. A power divider network are employed to distribute T-junction divider. As result, the proposed antenna get gain of 14[dBi] at 10.525[GHz].