• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1099-1105
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• 2005

TRL error correction method is widely used for measuring high frequency device mounted on PCB. In order to correct error more precisely, the characteristic impedance of standard transmission line should be known mounted for error correction. The capacitance per the unit length of transmission line is calculated by using standard transmission line which terminate resistor additionally at previous method and the characteristic impedance of standard transmission line is calculated with fitting method according to frequency, but the characteristic impedance extracted by a manufacturing inaccuracy is influenced. In this study, a novel method can reduce the manufacturing inaccuracy using measured s-parameters and can extract more accurate characteristic impedance than the previous method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.515-518
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• 2004

The Piezoelectric ceramics for AE(Acoustic Emission) sensor are desired large electromechanical coupling factor, high mechanical quality factor and good characteristic resonance frequency. In this study, the empirical formula of specimens is used $0.9Pb(Zr_xTi_{1-x})O_3-0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$ (PZT-PMNS). The piezoelectric and dielectric characteristic are investigated by sintering temperature and value of x as functions of $Ti^{2+},\;Zi^{2+}$ mol rate. MPB(morphotropic Phase boundary) is defined in the x=0.522. Because it is appeared to the best piezoelectric and dielectric characteristic in the x=0.522, it can be application by AE sensor. PZT-PMNS ceramics without pre-amplifier and filter are tested for detecting of arc signal. The detection characteristic is evaluated wave form, frequency distribution.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.109-114
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• 2019

In this paper, simulations of S-parameter and characteristic impedance for the probe pin are performed and its high-frequency performance is analyzed. The probe pins are arranged with one signal pin in the center and four ground pins on the top, bottom, left and right sides. The insertion loss and return loss of the probe pin are calculated while increasing the separation between the probe pins to 0.35 mm, 0.40 mm, and 0.50 mm, respectively. It is confirmed that the probe pin has different features of the insertion loss due to its periodic resonance phenomenon. Effect of the characteristic impedance on pitch and assignment of the probe pin is also analyzed. It is verified that there are a number of ground pins whose characteristic impedance is close to 50 Ω.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.152-160
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• 2013

In this paper, to the aim of wideband SSN(Simultaneous Switching Noise) suppression characteristic, investigation of spiral resonator are used in conjunction with bead which is commonly used for noise suppression method. Bead works effectively to suppress the power noise up to the first harmonic of fundamental frequency, 0.8 GHz, and spiral resonator suppress noise well in the frequency range of SRF(Self Resonance Frequency) which is inversely proportional to the length of spiral. Thus, when bead used in conjunction with a spiral the noise suppression characteristic is determined by the one of higher impedance element of the two in the frequency range and achieves more broadband filtering characteristic. The case for using 22 nH bead turns out 4.8, 2.0, 0, and, 0.6 dB, and the case for using 22 nH bead in conjunction with 3-turns spiral achieves more wideband characteristic of 9.5, 8.3, 6.1, and 9.9 dB power noise suppression performances at the first, second, third, and fourth harmonics, respectively. The peak-to-peak voltage levels decrease from 76 mV to 56 mV using 22 nH bead, and the level decrease rapidly to 34 mV when using in conjunction with bead and 3-turn spiral. Thus more wideband SSN suppression characteristic can be achieved using bead with spiral.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1585-1591
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• 2009

This paper describes a new method for extracting characteristic impedance of transmission line using Substrate Integrated Artificial Dielectric (SIAD). The new procedure to calculate the characteristic impedance of SIAD transmission line is described with the proper equations and basic transmission line theory. The characteristic impedance is determined as an almost fixed value in the proposed method, while it fluctuates according to frequency in the previous method. As the result, the effective dielectric constant of SIAD transmission line is calculated as a fixed value rather than fluctuating one. In order to show the validity of the proposed method, SIAD microstrip lines are simulated and measured, and characteristic impedances and effective dielectric constant are calculated and compared to the previous method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.165-172
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• 2019

Using two or more coaxial lines, if one port is connected in series and the other port is connected in parallel, it can be implemented the wideband transmission line transformer(TLT). Because the wideband TLT utilizes the outer conductor of the coaxial line, it is difficult to predict the characteristics. In this paper, based on the analysis for the transfer characteristic(S21) according to the loss of the each line in ${\lambda}/4$-microstrip line TLT, the operating characteristic of the fabricated wideband 4:1 TLT using two $25{\Omega}$-coaxial lines is investigated. The fabricated wideband TLT shows the notch characteristic in which the transfer signal sharply decreases at ${\lambda}/4$ frequency of the coaxial line and has a value within -0.2dB of the transfer characteristic(S21) in $0.06{\sim}0.2{\lambda}$ frequency range of the coaxial line. This transfer characteristics(S21) can change the operating frequency range slightly and set the optimum transfer characteristic(S21) at the desired frequency by changing the length of the microstrip line.

• Steel and Composite Structures
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• v.18 no.1
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• pp.255-271
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• 2015

This paper presents the natural frequency of a composite girder with corrugated steel web (CGCSW). A corrugated steel web has negligible in-plane axial stiffness, due to the unique characteristic of corrugated steel webs, which is called the accordion effect. Thus, the corrugated steel web only resists shear force. Further, the shear buckling resistance and out-of-plane stiffness of the web can be enhanced by using a corrugated steel web, since the inclined panels serve as transverse stiffeners. To take these advantages, the corrugated steel web has been used as an alternative to the conventional pre-stressed concrete girder. However, studies about the dynamic characteristics, such as the natural frequency of a CGCSW, have not been sufficiently reported, and it is expected that the natural frequency of a CGCSW is different from that of a composite girder with flat web due to the unique characteristic of the corrugated steel web. In this study, the natural frequency of a CGCSW was investigated through a series of experimental studies and finite element analysis. An experimental study was conducted to evaluate the natural frequency of CGCSW, and the results were compared with those from finite element analysis for verification purpose. A parametric study was then performed to investigate the effect of the geometric characteristics of the corrugated steel web on the natural frequency of the CGCSW. Finally, a simplified beam model to predict the natural frequency of a CGCSW was suggested.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.185.2-185.2
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.14-15
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• 2000

We study the microwave characteristics of traveling-wave photodetector using the finite-difference time-domain method. We present two parameters for design, the width of PIN region and the thickness of i-layer, and analyze TWPD's property in frequency domain.

• Korean Journal of Adult Nursing
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• v.14 no.1
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• pp.102-113
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• 2002

Purpose: This study was designed to identify the relationship between self reported climacteric symptoms, self concept and depression in middle aged women. Method: Data were collected through self-reported questionaires which were constructed to include a climacteric symptoms, self-concept and depression of middle-aged women scale. The subjects for this study were 102 women between 40-59 years of age living in P city. The data were analyzed by descriptive statistics, t-test, ANOVA, Pearson Correlation Coefficient. Results: The results obtained from this study were as follows : 1) The relationship between self reported climacteric symptoms and self concept was statistically significant with a negative correlation (r=-0.4862, P0.001). The relationship between self reported climacteric symptoms and depression had a statistically significant positive correlation (r=0.5393, P<0.001). The Relationship between self-concept and depression had a statistically significant negative correlation (r=-0.3769, P<0.001). 2) General characteristic variables significantly related to self reported climacteric symptoms were age (F=3.13, P<0.05) and frequency of pregnancy (F=3.24, P<0.05). General characteristic variables significantly related to frequency of self-concept were age (F=3.13, P<0.05), education level (F=2.97, P<0.05) and occupation (t=1.84, P<0.05). General characteristic variables significantly related to depression were age (F=3.12, P<0.05) and number of children (t=3.59, P<0.05). 3) The obstetrical characteristic variable significantly related to self-reported climacteric symptoms was the frequency of pregnancy (t=3.24, P<0.05). Conclusion: This study shows possible implications for nursing intervention for middle-aged women's health to prevent and relieve climacteric symptoms.