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Graduate Exam Abstract


Elene Chobanyan

Ph.D. Final

December 1, 2014, 1:00 pm - 3:00 pm

Deans Conference Room ENGR B214

Higher Order Volume/Surface Integral Equation Modeling of Antennas and Scatterers Using Diakoptics and Method of Moments


Abstract: The principal objective of this dissertation is to develop, test, and optimize accurate, efficient, and robust computational methodology and tools for modeling of general antennas and scatterers based on solutions of electromagnetic integral equation formulations using the method of moments (MoM) and diakoptics. The approaches and implementations include the volume integral equation (VIE) method and its hybridization with the surface integral equation (SIE) method, in two ways. The first way combines the VIE method for dielectric parts and the SIE method for metallic parts of the structure. The second way performs subdivision of the entire structure into SIE domains of different constant permittivities, while modeling the inhomogeneity within each domain by the VIE method and employing different Green’s functions, with describing the inhomogeneity within each domain in terms of a perturbation with respect to the background permittivity. The first approach is very suitable for analysis of composite wire-plate-dielectric radiation/scattering structures. The second approach provides a particularly efficient solution to problems involving inhomogineities embedded within high-contrast homogeneous dielectric scatterers. The efficiency of computation is enhanced by applying the diakoptic domain decomposition. In the VIE-SIE diakoptic method, the interior diakoptic subsystems containing inhomogeneous dielectric materials are analyzed completely independently applying the VIE-SIE MoM solver, and the solution to the original problem is obtained from linear relations between electric and magnetic surface-current diakoptic coefficients on diakoptic surfaces, written in the form of matrices. The techniques implement Lagrange-type generalized curved parametric hexahedral MoM-VIE volume elements and quadrilateral MoM-SIE and diakoptic patches of arbitrary geometrical-mapping orders, and divergence-conforming hierarchical polynomial vector basis functions of arbitrary current expansion orders. The hexahedra can be filled with inhomogeneous dielectric materials with continuous spatial variations of the permittivity described by Lagrange interpolation polynomials of arbitrary material-representation orders. Numerical computation is further accelerated by MPI parallelization to enable analysis of large electromagnetic problems.

Adviser: Branislav Notaros
Co-Adviser: N/A
Non-ECE Member: Iuliana Oprea
Member 3: Steven Reising, V. Chandrasekar, Ali Pezeshki
Addional Members: N/A

Publications:

1. E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Double-Higher-Order Large-Domain Volume/Surface Integral Equation Method for Analysis of Composite Wire-Plate-Dielectric Antennas and Scatterers”, IEEE Transactions on Antennas and Propagation, vol. 61, No. 12, pp. 6051-6063, December 2013
2. E. Chobanyan, , D. I. Olćan, M. M. Ilić, and B. M. Notaroš, ”Volume Integral Equation Based Diakoptic Domain-Decomposition Method for 3-D Electromagnetic Scattering Analysis”, IEEE Transactions on Antennas and Propagation, under revision
3. E. Chobanyan, M. M. Ilić, and B. M. Notaroš, ” Lagrange-type Modeling of Continuous Permittivity Variation in Double-Higher-Order Volume Integral Equation Method”, Radio Science, under revision
4. M. Kabir, Md. A. H. Talukder, R. Khazaka, M. A. Dolatsara, E. Chobanyan, A. Smull, S. Roy, and B. M. Notaroš, “Non-Intrusive Pseudo Spectral Approach for Stochastic Macromodeling of EM Systems using Deterministic Full-wave Solvers”, 23rd Conference on EPEPS 2014, 26-29 October, 2014
5. B. M. Notaroš, M. M. Ilić, D. I. Olćan, M. Djordjević, A. B. Manić, and E. Chobanyan, ”Hybrid Higher Order Numerical Methods in Electromagnetics”, International Conference on Electromagnetics in Advanced Applications, 3-9 August, 2014
6. E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Scattering Analysis Using Generalized Volume-Surface Integral Equation Method of Moments”, Submitted for 2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 6-12 July, 2014
7. N. J. Šekeljić, A. B. Manić, E. Chobanyan, M. Thurai, V. N. Bringi, and B. M. Notaroš , “Electromagnetic Scattering by Oscillating Rain Drops of Asymmetric Shapes”, Submitted for 2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 6-12 July, 2014
8. A. B. Manić, E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Parallelization of Double Higher Order FEM and MoM Techniques”, Submitted for 2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 6-12 July, 2014
9. E. Chobanyan, N. J. Šekeljić, A. B. Manić, B. M. Notaroš , and M. M. Ilić, “Atmospheric Particle Scattering Computation Using Higher Order MoM-SIE Method”, 2013 IEEE Antennas and Propagation Society International Symposium (APSURSI), 7-12 July, 2013
10. E. Chobanyan, D. I. Olćan, M. M. Ilić, and B. M. Notaroš, “Combining Diakoptic, VIE-MoM, and SIE-MoM Approaches in Analysis of Dielectric Scatterers”, 2013 IEEE Antennas and Propagation Society International Symposium (APSURSI), 7-12 July, 2013
11. J. Notaros, E. Chobanyan, V. Chandrasekar, and B. M. Notaros, “Accurate and Efficient Full-Wave Electromagnetic Analysis of Scattering from Hailstones,” 2013 IEEE Antennas and Propagation Society International Symposium, July 7-12, 2013
12. E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Higher Order Volume and Surface Integral Equation Modeling of 3-D Scattering and Radiation Problems”, USNC-URSI National Radio Science Meeting, January 9-12, 2013
13. E. Chobanyan, J. Notaroš, V. Chandrasekar, and B. M. Notaroš, “Accurate Electromagnetic Modeling of Melting Hail”, USNC-URSI National Radio Science Meeting, January 9-12, 2013
14. E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Efficient higher order volume-integral-equation modeling of dielectric scatterers”, 2012 IEEE Antennas and Propagation Society International Symposium (APSURSI), 8-14 July, 2012
15. N. J. Šekeljić, E. Chobanyan, M. M. Ilić, and B. M. Notaroš, “Rules for Adoption of Expansion and Integration Orders in Moment-Method Computation of Electromagnetic Scattering and Radiation”, USNC-URSI National Radio Science Meeting, January 4-7, 2012


Program of Study:
ECE444
ECE512
ECE641
ECE642
MATH560
MATH652
ECE779
N/A