• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.225-232
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• 2018

This paper proposed the optimization method of the extremely low numerical-dispersion finite-difference time-domain (ELND-FDTD) method based on the H(2,4) scheme for wideband and extremely accurate electromagnetic properties of lossy material, which has a constant conductivity and relative permittivity. The optimized values of three variables are calculated for the minimum numerical dispersion errors of the proposed FDTD method. The excellent accuracy of the proposed method is verified by comparing the calculated results of three different FDTD methods and the analytical results of the two-dimensional dielectric cylinder scattering problem.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.605-611
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• 2002

A simple and efficient analysis method of the suspended stripline using the finite-difference time-domain (FDTD) method is presented. New FDTD equations are derived using the contour path FDTD concept for the Yee cell which contains a dielectric sheet. The characteristic impedance and the effective dielectric constant of the suspended stripline are calculated using our proposed FDTD method. Using the calculated results, a 5-element lowpass filter is designed and fabricated. Our proposed FDTD method is validated by the measured data of the fabricated lowpass filter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.10
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• pp.38-45
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• 2002

This paper presents the new Compact 2D ADI-FDTD(Alternating-Direction Implicit Finite-Difference Time-Domain) method, where the time step is no longer restricted by the numerical stability condition. This method is an accelerating algorithm for the conventional Compact 2D FDTD method. To validate this algorithm, we have analyzed the dispersion characteristics of the hollow rectangular waveguide and the shielded microstrip line. The results of the proposed method are very well agreed with those of both the conventional analytic method and the Compact 2D FDTD method. The CPU time for analysis of this method is very much reduced compared with the conventional Compact 2D FDTD method. The proposed method is valuable as a fast algorithm in the research of dispersion characteristics of the waveguide structures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.584-590
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• 2003

In this paper, the numerical characteristics of the recently developed Envelope ADI-FDTD are investigated. Through numerical simulations, it is shown that the unconditional stability of the Envelope ADI-FDTD is independent of time step size and we can get better dispersion accuracy than the traditional ADI-FDTD by analyzing the envelope of the signal. This fact gives the opportunity for extending the temporal step size to the Nyquist limit in certain cases. Numerical results show that the Envelope ADI-FDTD can be used as an efficient electromagnetic analysis tool especially in the single frequency or band limited systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.63-69
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• 1999

In this paper, we analyze the cutoff frequencies of the TEM Cells by the FDTD, and introduce new boundary condition for the FDTD to identify the modes. Then, we confirm efficiency of the FDTD comparing results in previous papers. We also give our opinion from the results by FDTD to the arguments, which is resulted from different results about cutoff frequencies in the TEM Cells, especially the symmetric TEM Cells.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.34-40
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• 2004

This paper presents an analysis of SAR(Specific Absorption Rate) distribution characteristics in a head model using FDTD(Finite Difference Time Domain). In this study human head was modelled in four elements-layered structure, consisting of skin, fat, skull and brain. To calculate the electromagnetic fields wihtin the head model, FDTD method was used. In the FDTD method, the electromagnetic wave is analyzed by solving a Maxwell's equations repeatedly. For the calculation, distance between power source and head model increased by 10[m]. Power density and incident electric field intensity were calculated. Based on the incident electric field, the program which calaculated internal electric fields intensity and SAR calculation of the head model were developed. The results of developed program using FDTD were compared with those of a commericial programs, which showed the availability and usefulness of the suggested scheme in this paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.407-415
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• 2011

The stability condition and wideband characteristics of 3D ID-FDTD algorithm which has low dispersion error with isotropic dispersion are presented in this paper. 3D ID-FDTD method was proposed to improve the defect of the Yee FDTD such as the anisotropy and large dispersion error. The published paper calculated the stability condition of 3D ID-FDTD algorithm by using numerical method, however, it is thought that the examples were not sufficient to verify the stability condition. Thus, in this paper, various simulations are included in order to hold reliability under the conditions that the plane wave propagation is assumed with a single frequency and a wideband frequency. Also, the 3D ID-FDTD algorithm is compared to those that have the similar FDTD algorithm with ID-FDTD such as Forgy's method and non-standard FDTD method in a wideband. Finally, the radar cross section(RCS) for the large sphere with high dielectric constant is calculated.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.3-14
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• 1995

The broadband input impedance, the input power and the radiation pattern of the monopole antenna attached to the handy phone operated at 800MHz are calculated by using the Finite Difference Time Domain(FDTD) Method. For the FDTD analysis of frequency characteristics of monopole antenna, the handy phone is modeled with the geometry that the monopole antenna is connected to a conducting box, and the modified FDTD algorithm[11] used the thin wire appproximation method and the Maxwell's integral equation from the original Yee algorithm is applied for the analysis of the wire structure. Also, by means of finding the current distribution directly from circumferencial magnetic filelds around the monopole antenna and the conducting box, the radiation pattern is calculated to observe the influence of the conducting box, and is compared with the results of the known mothod for the FDTD calculation of radiation pattern, For the experiments, the handy phone of which full length including antenna is .lambda. $\lambda$/2 is manufactured and we confirm that all computation results are agree well with the mea- sured values.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.4
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• pp.101-112
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• 2004

In this paper, we developed a numerical analysis model by using ADI-FDTD method to analyze three-dimensional interconnect structure. We discretized maxwell's curl equation by using ADI-FDTD. Using ADI-FDTD method, a sampler circuit designed from 3.3 V CMOS technology is simplified to 3-metal line structure. Using this simplified structure, the time delay and signal distortion of complex interconnects are investigated. As results of simulation, 5∼10 ps of delay time and 0.1∼0.2 V of signal distortion are measured. As demonstrated in this paper, the full-wave analysis using ADI-FDTD exhibits a promise for accurate modeling of electromagnetic phenomena in high-speed VLSI interconnect.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.528-537
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• 2002

In this paper, the extended FDTD is used for the analysis of microwave circuits including active elements. Lumped elements such as R, L, C which are inserted into a microstrip line are analyzed with the FDTD lumped element modeling. Parasitic capacitance and inductance could be obtained using network modeling and so it is sure that FDTD lumped element modeling makes it possible to get more accurate data which include parasite components. Moreover, a balanced mixer using two diodes that are modeled by an extended FDTD is designed and the more exact characteristic of the mixer is acquired than in current circuit simulator.