• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.9-17
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• 1999

This investigation is the result of the structural analysis by finite element method for optimal design of the cross beam with circular holes of the electric car-body. in order to install the air pipe and electric wire pipe that correspond signal between electric machines for the control system and to reduce the weight of the electric car-body, several circular areas from a cross beam should be taken off. What we want to perform is the optimal design of a cross beam with circular holes to posses equal stress in comparison with no hole cross beam. first, no hole cross beam as basic modal be chosen, executing the analysis, reviewing the distribution of stress and displacement at each location. several parameter should be adopted from the cross beam geometry like the location and shape of the hole to affect the maximum stress and displacement. So the analysis was executed by finite element analysis for finding optimal design parameter to the change of the location and shape of the circular hole. finally, the optimal design of the cross beam with circular holes was obtained and the maximum equivalent stress was compared with no hole cross beam at each location.

• 전자공학회논문지 IE
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• v.44 no.2
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• pp.1-7
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• 2007

The increasing high frequency capabilities of CMOS have resulted in increased RF and analog design in CMOS. Design of RF and analog circuits depends critically on device S-parameter characteristics, magnitude of real and imaginary components and their behavior as a function of frequency. Utilization of scaled high performance CMOS technologies poses challenges as concerns for reliability degradation mechanisms increase. It is important to understand and quantify the effects of the reliability degradation mechanisms on the S-parameters and in turn on small signal model parameters. Various physical effects influencing small-signal parameters, especially the transconductance and capacitances and their degradation dependence, are discussed in detail. The measured S-parameters of H-gate and T-gate devices in a frequency range from 0.5GHz to 40GHz. All intrinsic and extrinsic parameters are extracted from S-parameters measurements at a single bias point in saturation. In this paper we discuss the analysis of the small signal equivalent circuits of RF SOI MOSFET's verificated for the purpose of exacting the change of parameter of small signal equivalent model followed by device flame.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.47-53
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• 2011

The signal transmission properties of the connector such as insertion loss and return loss are investigated using analysis procedure of S-parameter simulation, equivalent model extraction, and characteristic impedance calculation. S-parameter simulation is performed by connector's modeling and solving based on 3-dimensional finite element method. The connector's equivalent model of ${\pi}$ type is are proposed and extracted with an optimization process of circuit analysis simulator. The characteristic impedance of the connector is calculated with results of circuit analysis simulation and S-parameter data. According to the connector's characteristic impedance, it's revised design is carried out. In this work, the connector's effective contact area is increased and its body is applied as a high dielectric material in order to increase its capacitance and then obtain impedance matching. Therefore, return loss of the connector is improved by approximately 10 dB due to its design revision.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.38-51
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• 2000

The study on the mechanical behavior of a spot-welded specimen is largely divided into the quasi-static overload failure analysis and the fatigue failure prediction. The main issue in an overload analysis is to examine the critical loads, thereby providing a generalized overload failure criterion. As the welding spot forms a singular geometry of an external crack type, fatigue failure of spot-welded specimens can be evaluated by means of a fracture parameter. In this study, we first present the limit loads of 4 representative types of single spot-welded specimens in terms of the base metal yield strength and specimen geometries. Recasting the load vs. fatigue life relationships experimentally, obtained here, we then predict the fatigue life of spot-weld specimens with a single parameter denoted the equivalent stress intensity factor. This crack driving parameter is demonstrated to successfully describe the effects of specimen geometry and loading type in a comprehensive manner. The suggested fatigue life formula for a single spot weld can play a key, role in the design and assessment of spot-welded panel structures, in that the fatigue strength of multi-spots is eventually determined by the fatigue strength of each single spot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1434-1439
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• 2012

Vehicle is a dynamic system combined with various parameters. Dynamic characteristics of a vehicle can vary with the change of these parameters. To investigate the effect of the design parameter on vehicle handling performance the sensitivity analysis is carried out by the numerical method. The vehicle model is described by equivalent cornering stiffness that considers parameters of suspension and steering system. As the analysis results show the effect on the static and dynamic characteristics of the vehicle system, the sensitivity analysis can be used for synthesis of the design parameters to improve the vehicle handling characteristics at the design stage as well as during the vehicle test under development.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.645-648
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• 1998

We used a three-dimensional inductance extraction program, Fasthenry for optimal design of the spiral inductors on silicon substrate. The inductance and quality factor of the spiral inductors with various design parameters were calculated so that the optimal parameter value was determined. The spiral inductors then were fabricated using different foundary processes and were measured using the network analyzer and microwave probes. The pad and other parasitics of measurement system were de-embedded using the y-parameter calibration technique. the inductors fabricated using the LG 0.8um process and HP 0.5um process showed the quality factor of 5.8 and 3, respectively. Finally the equivalent circuit farameters of the spiral inductors on silicon substrate were extracted from the measurement data using the matlab.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.2
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• pp.164-169
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• 2002

This paper reports on design and fabrication of near field probe operating at 300~3000 MHz. Design parameters are extracted by equivalent circuit of E-field probe and simulation using S parameter is performed to predict probes performance. The probe consists of a dipole antenna with 3.25 mm length, a zero bias Schottky diode and a highly resistive transmission line. A TEM cell was used for performance evaluation.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.393-396
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• 2000

Repeater Duplexer of 800MHz band consists of 4pole transmitter band pass filter, receiver band pass filter and branch circuit. Circuit parameter of Duplexer such as coupled capacitance of equivalent circuit was drawn out and used to coupled line characteristics impedance (Zoo, Zoe) that satisfied resonator condition and attenuation condition. Simulation was carried out by the ADS(Advanced Design System) were obtained good attenuation characteristics (869~894MHz： 65㏈(Min.),824~349MHz： 65㏈(Min.)

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.413-416
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• 2001

In high frequency range, RF circuit design without considering shielding effect can cause several significant changes due to increase in parasitic capacitance and inductance between RF signal lines and shielding box. In this paper, bandpass filter has been made to measure the shielding effect and its s-parameter has been measured by Vector Network Analyzer (VNA). Equivalent circuit model including the shielding effect has been constructed with the lumped elements extracted from the 3D electromagnetic simulator, Maxwell SI. Then, the validity of the model is verified using microwave circuit simulator, ADS (Advanced Design System).

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.281-284
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• 2004

In Recent, it became necessary to envelope the technology about electrodeless fluorescent lamp according to demand of the electrodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electrodeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter So it is of the utmost importance to design antena and inverter. Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Phase, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electrodeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density.