Hosang Lee

Enhancement of Differential Signal Integrity by Employing a Novel Face Via Structure

This paper proposes a novel differential via structure, which is dubbed as face via, to improve the impedance discontinuities at the via transition. The performance of the proposed face via is verified by simulated and measured impedances in time domain reflection responses and by equivalent circuit modeling. In this paper, the conventional cylinder via and the proposed face via were designed and fabricated to demonstrate the effectiveness of the face via in differential signal channels. The analysis indicates that the proposed differential via structure provides a very effective way to minimize the impedance discontinuities at vias by controlling the size of face in the via. The analysis of the eye diagram identified the improvement of signal integrity in channel characteristics. Furthermore, in order to consider the complexity in digital system at high speed, the performance of face vias in multiple via transitions and the effect of return current vias are also investigated. Finally, the effectiveness of the proposed face via has been successfully validated by the simulation and experiment results.

Analysis of electromagnetic field interference between an antenna and a multiple-noise source using active scattering parameters

This paper proposes an analysis method for electromagnetic field interference between an antenna and adjacent noise sources, using active scattering parameters. Electromagnetic field interference can be analyzed by measurement or simulation of the scattering parameters. In this paper, a multiple-band antenna and a multiple-noise source were designed and fabricated to analyze the electromagnetic field interference between them. The proposed analysis method employs active scattering parameters, whose validity has been verified both experimentally and through simulation.

Efficient circuit and EM model of electrostatic discharge generator

In this work, a new technique for an efficient, simple, and fast equivalent circuit and full wave numerical modeling of the electrostatic discharge (ESD) generator is presented. A novel circuit model of the NoiseKen ESD simulator is proposed based on the frequency domain measurement of the standard waveform calibration setup. The simple full wave electromagnetic model of the same generator, which requires much less computation resources, is also proposed using commercial CST Microwave Studio software. The reliability of the proposed models as an authentic ESD excitation source is validated through an example discharge application. The good agreement between the ESD reference waveform obtained through measurement, circuit model, and 3-D model of the generator is observed.

Theory, Simulation, and Experiment on Extended Mixed-Mode S-Parameters in Three-Conductor Lines

This paper proposes novel mixed-mode <italic>S</italic>-parameters, which are dubbed as “extended mixed-mode <italic>S</italic>-parameters.” The extended mixed-mode <italic>S</italic>-parameters were applied to three-conductor transmission lines, resulting in the independent differential and common modes using the current division factor of three-conductor transmission lines. By contrast to the conventional mixed-mode <italic>S</italic> -parameters, there are no cross-mode <italic>S</italic>-parameters in the extended mixed-mode <italic>S</italic> -parameters, even in the asymmetrical conductor transmission lines. In addition, two new mode conversion matrices, which contain the current division factor, are also proposed to convert the extended mixed-mode <italic>S</italic> -parameters to the standard <italic>S</italic>-parameters. The validity of the proposed extended mixed-mode <italic>S </italic>-parameters and the mode conversion method were confirmed by comparing the <italic>S</italic>-parameters from the theory, EM-simulation, and experiment as well.

Stochastic estimation of common mode radiated emission from a transmission line

Accurate estimation of an EMI characteristic of a given circuit at design stage is very difficult because of many uncertainties of parameters in the circuit. This is especially true when the symmetry of a circuit is broken in manufacturing, which was supposed to be in symmetry in the first place. When the symmetry is broken, quite a lot common mode radiation could be occurring, which is not easy to predict for a circuit designer at the design stage. In this paper, we propose a new simulation methodology for estimating common mode radiated emission from a transmission line using a generalized polynomial chaos (gPC), which is based stochastic approach, and show its validness to predict the common mode radiation from a transmission line.

Electric and magnetic field shielding evaluation of board level shield can using TEM cell

This paper proposes a simple electric and magnetic field shielding evaluation method of board level shield can using Transverse Electro-Magnetic cell (TEM cell). Small sized electric and magnetic probes (antennas) are installed on the top of a TEM cell with and without shield can below the probe, and 3-port S-parameters are measured, which are used to calculate the electric and magnetic dipole moments of the probes transferred to the other two ports in the TEM cell. The calculated data effectively evaluated the shielding effectiveness of the shield cans with various ventilation holes in both electric field and magnetic field, separately. Finally, the measured shielding effectiveness was validated by numerical simulation and thus reliable results were obtained.