Accurate FDTD modelling for dispersive media using rational function and particle swarm optimisation

Chung, Haejun; Ha, Sang-Gyu; Choi, Jeong-Hwa; Jung, Kim Hyun

doi:10.1080/00207217.2014.966779

Cited by 13 publications

(7 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…First, we consider human blood from 300 MHz to 3 GHz. The modified Lorentz parameters are extracted by using the particle swarm optimization [29,30] for the complex relative permittivity data [31]. They are 0 = 6.9379 ⋅ 10 21 , 1 = 1.5057 ⋅ 10 12 , 0 = 6.1637 ⋅ 10 18 , 1 = 4.5425 ⋅ 10 10 , 2 = 1, and ,∞ = 31.1662.…”

Section: Resultsmentioning

confidence: 99%

Newmark-FDTD Formulation for Modified Lorentz Dispersive Medium and Its Equivalence to Auxiliary Differential Equation-FDTD with Bilinear Transformation

Choi

Cho

Park

et al. 2019

International Journal of Antennas and Propagation

Self Cite

View full text Add to dashboard Cite

The finite-difference time-domain (FDTD) method has been popularly utilized to analyze the electromagnetic (EM) wave propagation in dispersive media. Various dispersion models were introduced to consider the frequency-dependent permittivity, including Debye, Drude, Lorentz, quadratic complex rational function, complex-conjugate pole-residue, and critical point models. The Newmark-FDTD method was recently proposed for the EM analysis of dispersive media and it was shown that the proposed Newmark-FDTD method can give higher stability and better accuracy compared to the conventional auxiliary differential equation- (ADE-) FDTD method. In this work, we extend the Newmark-FDTD method to modified Lorentz medium, which can simply unify aforementioned dispersion models. Moreover, it is found that the ADE-FDTD formulation based on the bilinear transformation is exactly the same as the Newmark-FDTD formulation which can have higher stability and better accuracy compared to the conventional ADE-FDTD. Numerical stability, numerical permittivity, and numerical examples are employed to validate our work.

show abstract

Section: Resultsmentioning

confidence: 99%

Newmark-FDTD Formulation for Modified Lorentz Dispersive Medium and Its Equivalence to Auxiliary Differential Equation-FDTD with Bilinear Transformation

Choi

Cho

Park

et al. 2019

International Journal of Antennas and Propagation

Self Cite

View full text Add to dashboard Cite

show abstract

“…were challenging due to the difficulty of developing a time domain dispersion model for them. Recently, the present authors have demonstrated a quadratic complex rational function (QCRF) model [19,20] for photovoltaic materials [21,22], thus in this work, we employ QCRF based FDTD method for a full-wave optical simulation (400 ~ 1200 nm) of perovskite/silicon tandem cells. To simulate a wafer-based c-Si in FDTD, we measure the absorption of a 2 micron-thick c-Si cell within a tandem cell, and then analytically extend to a larger thickness in the following manner.…”

Section: Theorymentioning

confidence: 99%

Optical approaches to improving perovskite/Si tandem cells

Chung¹,

Sun²,

Bermel³

2016

MRS Advances

Self Cite

View full text Add to dashboard Cite

Recently, metal-halide perovskites have demonstrated an extraordinarily rapid advance in single junction cell efficiency to over 20%, while still offering potentially low costs. Since the bandgap is larger than the ideal single-junction value, perovskite-based tandem cells can theoretically offer even higher efficiencies. Instead, however, the record tandem cell performance in experiments to date has come in slightly below that of record single junctions, although slightly higher than the same single junctions. In this work, we consider both how this disconnect can be explained quantitatively, and then devise experimentally feasible, variance-aware approaches to address them. The first stage of our approach is based on reconfiguring dielectric front coatings to help reduce net reflected power and balance junction currents by reshaping the reflection peaks. This method could be applied to post-fabrication stage of perovskite/c-Si tandem cells, and also applicable to cell and module level structures. In the second stage of our approach, we can almost entirely eliminate Fresnel reflection by applying a conformal periodic light trapping structure. In the best case, a short circuit current (Jsc) of 18.0 mA/cm2 was achieved, after accounting for 4.8 mA/cm2 of parasitic loss and 1.6 mA/cm2 reflection loss. Further improvements may require a change in the baseline materials used in perovskite cells.

show abstract

“…In order to accurately model the behavior of the materials used in the experiments (such as c-Si and silver), a recently developed time-domain dispersion model, called quadratic complex rational function (QCRF), is used [25,33]. Other experimental materials of interest (e.g., ZnO and ITO) were assumed to be non-dispersive and non-absorptive, since thin ITO and ZnO layers generally appear transparent in the visible wavelengths and their single path absorption of 70 nm ITO does not exceed 2.42% for near-infrared wavelengths below 1000 nm.…”

Section: Parasitic Absorption Modelingmentioning

confidence: 99%

Flexible flux plane simulations of parasitic absorption in nanoplasmonic thin-film silicon solar cells

Chung¹,

Jung

Bermel³

2015

Opt. Mater. Express

View full text Add to dashboard Cite

Photovoltaic light trapping theory and experiment do not always clearly demonstrate how much useful optical absorption is enhanced, as opposed to parasitic absorption that cannot improve efficiencies. In this work, we develop a flexible flux plane method for capturing these parasitic losses within finite-difference time-domain simulations, which was applied to three classical types of light trapping cells (e.g., periodic, random and plasmonic). Then, a 2 µm-thick c-Si cell with a correlated random front texturing and a plasmonic back reflector is optimized. In the best case, 36.60 mA/cm 2 J sc is achieved after subtracting 3.74 mA/cm 2 of parasitic loss in a 2-µm-thick c-Si cell slightly above the Lambertian limit.

show abstract

Accurate FDTD modelling for dispersive media using rational function and particle swarm optimisation

Cited by 13 publications

References 24 publications

Newmark-FDTD Formulation for Modified Lorentz Dispersive Medium and Its Equivalence to Auxiliary Differential Equation-FDTD with Bilinear Transformation

Newmark-FDTD Formulation for Modified Lorentz Dispersive Medium and Its Equivalence to Auxiliary Differential Equation-FDTD with Bilinear Transformation

Optical approaches to improving perovskite/Si tandem cells

Flexible flux plane simulations of parasitic absorption in nanoplasmonic thin-film silicon solar cells

Contact Info

Product

Resources

About