Session: TU3C | Hybrid and Optimized Time-Domain Methods |
Chair: | Nathan Bushyager, Northrop Grumman Electronic Systems |
Co-Chair: | Samir El-Ghazaly, University of Arkansas |
Abstract: | The papers presented in this session demonstrate the importance of using techniques suited to the phenomena under study. The methods presented focus on solving problems where existing techniques show deficiencies, or dissimilar features recommend the use of multiple techniques. Two of the papers incorporate what are traditionally separate techniques, one to combine the study of large homogenous regions with finely detailed ground planes, and another combines electromagnetic and solid state interactions. The remaining papers focus on the stability, efficiency, and adaptability to irregular boundaries. |
| | TU3C-01 | An Efficient Unconditionally Stable Three-Dimensional LOD-FDTD Method |
1234 | Q. Liu1, Z. D. Chen2, W. Yin1, 1Shanghai Jiao Tong University, Shanghai, China, 2Dalhousie University, Halifax, Canada |
| This paper presents an unconditionally stable three-dimensional (3-D) finite-difference time-method (FDTD) based on the locally one-dimension (LOD-FDTD) scheme. The unconditional stability is proven theoretically and validated numerically. Numerical dispersion of the method is also derived analytically. Through the dispersion analysis and a numerical example, the proposed LOD-FDTD method is found to use less memory and CPU time than the conventional unconditionally stable alternating-direction-implicit (ADI) FDTD and other LOD-FDTD methods but with the same level of numerical accuracy. The saving in CPU time can be more than 55% in comparisons with the ADI-FDTD method and more than 29% in comparisons with a previously reported LOD-FDTD method. |
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TU3C-02 | An Efficient Method for the Coupling of a Fully-Explicit Time-Domain Solid-State Hydrodynamic simulator with FDTD EM Solvers |
1727 | B. S. McGarvey, M. M. Tentzeris, GEDC, Atlanta, United States |
| This paper examines the implications of decoupling the FDTD grids between and FDTD Electromagnetic (FDTD-EM) and an FDTD Hydrodynamic semiconductor simulator. Excitation methods and responses are examined to determine feasibility for decoupling the space and time grids for significant computational savings. Additionally, a new fully-explicit leap-frog discretization of the Hydrodynamic model is is benchmarked with respect to several well known discretization methods. |
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TU3C-03 | Efficient TLM Sensitivity Analysis Exploiting Rubber Cells |
1408 | P. A. Basl, M. H. Bakr, N. K. Nikolova, McMaster University, Hamilton, Canada |
| The Adjoint Variable Method (AVM) is applied for the first time to perform sensitivity analysis for Transmission Line Modeling (TLM) using rubber cells with modified tensor properties. Rubber cells allow the conformal modeling of off-grid boundaries in the TLM domain using modified tensor properties. The scattering matrix of the rubber cell is analytically dependent on the dimensions of the modeled discontinuities. Using this property, an exact adjoint system is derived. The original and adjoint systems supply the necessary field information for the rubber cell based sensitivity calculations. Our technique is illustrated through sensitivity analysis and optimization of a waveguide bandpass filter. |
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TU3C-04 | Interfacing the TLM and the TWF Method using a Diakoptics Approach |
1471 | N. Fichtner1, S. Wane2, D. Bajon3, P. Russer1, 1TU München, München, Germany, 2Philips Semiconductors, Caen, France, 3Ecole nationale superieure de l'aeronautique et de e'space, Toulouse, France |
| A combination of the transmission line matrix (TLM) and the transverse wave formulation (TWF) method based on a diakoptics approach is presented for efficient modeling of multiscale and multilayered structures. The formal similarities of TLM and TWF enable a direct diakoptics approach, partitioning the simulation domain into a TLM and a TWF region. The computationally inefficient time--domain convolution of the TLM wave pulses with the impulse responses at the domain separation interfaces is replaced by a fast frequency--domain computation leading to a considerable reduction of the total simulation time. |
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TU3C-05 | The Meshless Radial Point Interpolation Method for Time-Domain Electromagnetics |
1392 | T. Kaufmann, C. Fumeaux, R. Vahldieck, ETH Zurich, Zurich, Switzerland |
| A meshless numerical technique based on radial point interpolation is introduced for electromagnetic simulations in time domain. The general class of meshless methods presents very attractive properties for addressing future challenges of electromagnetic modeling. Among the interesting aspects, the ability to handle arbitrary node distributions for conformal and multi-scale modeling can be mentioned first. Furthermore, the possibility of modifying the node distribution dynamically opens new perspectives for adaptive computations and optimization. The mathematical background of the radial point interpolation method and a two-dimensional implementation are presented here. The advantages of this meshless method are discussed and applied to a model consisting of a 90 degree H-plane waveguide bend. It is shown that solutions converge much faster using the ability of conformal modeling compared to a similar analysis in rectangular grids. |
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