The Finite-Difference Time Domain Method for Electromagnetics (original) (raw)
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Analyzing electromagnetic structures with curved boundaries on Cartesian FDTD meshes
IEEE Transactions on Microwave Theory and Techniques, 1998
In this paper, a new finite-difference time-domain (FDTD) algorithm is investigated to analyze electromagnetic structures with curved boundaries using a Cartesian coordinate system. The new algorithm is based on a nonorthogonal FDTD method. However, only those cells near the curved boundaries are calculated by nonorthogonal FDTD formulas; most of the grid is orthogonal and can be determined by traditional FDTD formulas. Therefore, this new algorithm is more efficient than general nonorthogonal FDTD schemes in terms of computer resources such as memory and central processing unit (CPU) time. Simulation results are presented and compared to those using other methods.
IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)
This This paper paper presents presents an an efficient efficient method method for for solving solving a a large large body body scattering scattering problem problem viz., viz., a a paraboloidal paraboloidal reflector reflector antenna antenna system system with with only only partial partial circular circular symmetry. symmetry. The The asymmetry asymmetry in in the the system system is is introduced introduced by by two two factors, factors, viz.. the the microstrip microstrip feed feed and and an an inhomogeneous inhomogeneous radome. radome. The The paper paper presents presents a a novel novel approach, approach, based based on on the the Reciprocity Reciprocity vi;, "equivalent aperture" still Principle Principle and and the the "equivalent aperture" theory, theory, to to handle handle the the asymmetry asymmetry problem problem and
An Elliptical Cylindrical FDTD Algorithm for Modeling Conformal Patch Antenna
IEEE Transactions on Antennas and Propagation, 2010
An explicit finite-difference time-domain (FDTD) method is described using a uniform elliptical cylindrical spatial grid for time-domain Maxwell's equations to accurately and efficiently model conformal elliptical cylindrical line-fed patch antennas and overcome stair-casing errors. Such errors are encountered when a Cartesian spatial grid is used for modeling curved surfaces. In addition, the method described in this paper obviates coding complexity encountered in modeling of curved surfaces which is manifest using CP-FDTD or CFDTD techniques. Characterizing expressions representing the absorbing boundary condition and Courant stability condition are presented and used to provide a highly effective algorithm to simulate conformal microstrip antennas. The proposed FDTD algorithm is validated against HFSS results showing excellent correlation.
Scattering Analysis of Periodic Structures Using Finite-Difference Time-Domain Method
Synthesis Lectures on Computational Electromagnetics, 2012
Synthesis Lectures on Computational Electromagnetics will publish 50-to 100-page publications on topics that include advanced and state-of-the-art methods for modeling complex and practical electromagnetic boundary value problems. Each lecture develops, in a unified manner, the method based on Maxwell's equations along with the boundary conditions and other auxiliary relations, extends underlying concepts needed for sequential material, and progresses to more advanced techniques and modeling. Computer software, when appropriate and available, is included for computation, visualization and design. The authors selected to write the lectures are leading experts on the subject that have extensive background in the theory, numerical techniques, modeling, computations and software development. The series is designed to: • Develop computational methods to solve complex and practical electromagnetic boundary-value problems of the 21st century. • Meet the demands of a new era in information delivery for engineers, scientists, technologists and engineering managers in the fields of wireless communication, radiation, propagation, communication, navigation, radar, RF systems, remote sensing, and biotechnology who require a better understanding and application of the analytical, numerical and computational methods for electromagnetics.
Efficient Implementation of BOR FDTD Algorithms in the Engineering Design of Reflector Antennas
2019
This work presents a modelling-based methodology for the design and evaluation of axi-symmetrical antennas, including horns, compact and large dual-reflector antenna systems. The starting concept of the antenna is an educated guess stemming from the engineer’s experience; however, further evaluation and optimization of that concept continue in a computational loop that involves a conformal FDTD algorithm in a BOR formulation. Our BOR FDTD retains the advantages of general-purpose 3D FDTD software, providing full-wave solutions and delivering key engineering parameters of antenna systems together with an insight into the distribution of the electromagnetic near-field, a useful feature to assess the mismatch of the horn due to the subreflector interaction. At the same time, the unique BOR formulation accelerates the analysis by orders in magnitude, making it practical to evaluate many designs within a manual or automatic optimization loop. We also show that BOR FDTD compares favourabl...
IEEE Transactions on Antennas and Propagation, 2000
This paper presents an efficient method to accurately solve large body scattering problems with partial circular sym metry. The method effectively reduces the computational domain from three to two dimensions by using the reciprocity theorem. It does so by dividing the problem into two parts: a larger 3-D region with circular symmetry, and a smaller 2-D region without circular symmetry. An finite-difference time-domain (FDTD) algorithm is used to analyze the circularly symmetric 3-D case, while a method of moments (MoM) code is employed for the nonsymmetric part of the structure. The results of these simulations are combined via the reciprocity theorem to yield the radiation pattern of the composite system. The advantage of this method is that it achieves significant savings in computer storage and run time in performing an equiv alent 2-D as opposed to a full 3-D FDTD simulation. In addition to enhancing computational efficiency, the FDTD algorithm used in this paper also features one improvement over conventional FDTD methods: a conformal approach for improved accuracy in mod eling curved dielectric and conductive surfaces. The accuracy of the method is validated via a comparison of simulated and mea sured results. Index Terms-finite-difference time-domain (FDTD) methods, method of moments, reciprocity theorem.
A Half Hollow Cylindrical Antenna (Hhca) Analysis Using the CFDTD Algorithm
Progress In Electromagnetics Research C, 2009
In this paper, a direct three dimensional Finite-Difference Time-Domain (3D-FDTD) approach is implemented to investigate the electromagnetic behavior of a Half Hollow Cylindrical Antenna. The conformal shape of this antenna is studied using the Conformal Finite-Difference Time-Domain (CFDTD). We shall prove that a variation of the antenna shape generates an important shift of the values of the resonant frequency (about 0.467 GHz). Compared with the planar shape, the geometrical shape reduces the space occupied by the antenna of about 36.28%.