| 1. |
- Capek, Miloslav, et al.
(författare)
-
Characteristic Mode Decomposition of Scattering Dyadic
- 2022
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Ingår i: 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2022 - Proceedings. - 9781665496582 ; , s. 283-284
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Konferensbidrag (refereegranskat)abstract
- This abstract describes the decomposition of a matrix representing a scattering dyadic into characteristic modes. Scattering dyadic, as compared to conventionally used impedance matrices, are independent of numerical method used to compute them and the same characteristic mode formulation can be used for decomposition of composite and inhomogeneous materials. The utilization of scattering dyadic makes it possible to synthesize characteristic modes which are orthogonal over prescribed portions of the far-field sphere, or ex-post decomposition of measured data. The theory is demonstrated on a simple example and its features are discussed.
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| 2. |
- Capek, Miloslav, et al.
(författare)
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Characteristic Mode Decomposition Using the Scattering Dyadic in Arbitrary Full-Wave Solvers
- 2023
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 71:1, s. 830-839
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Tidskriftsartikel (refereegranskat)abstract
- Characteristic modes are formulated using the scattering dyadic, which maps incident plane waves to scattered far fields generated by an object of arbitrary material composition. Numerical construction of the scattering dyadic using arbitrary full-wave electromagnetic solvers is demonstrated in examples involving a variety of dielectric and magnetic materials. Wrapper functions for computing characteristic modes in method-of-moments, finite-difference time domain, and finite element solvers are provided as supplementary material.
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| 3. |
- Capek, Miloslav, et al.
(författare)
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Cloaking Synthesis Based on Exact Re-analysis
- 2022
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Ingår i: 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2022 - Proceedings. - 9781665496582 ; , s. 293-294
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Konferensbidrag (refereegranskat)abstract
- A novel synthesizing procedure is introduced and employed to extract locally-optimal cloaking devices. Their performance is compared with fundamental bounds found using a convex optimization approach. The optimization method is based on a method-of-moments paradigm utilizing rank-1 updates of the structure iteratively performed based on a greedy algorithm. This approach produces locally optimal shapes and its incorporation into a global search strategy is described and applied. As compared to classical topology optimization schemes, no post-processing is required. Two canonical problems are solved and presented.
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| 4. |
- Capek, Miloslav, et al.
(författare)
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Fundamental Bounds for Volumetric Structures and Their Feasibility
- 2020
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Ingår i: 14th European Conference on Antennas and Propagation, EuCAP 2020. - 9788831299008
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Konferensbidrag (refereegranskat)abstract
- Fundamental bounds on antenna and scattering metrics are presented in this paper utilizing volumetric method of moments. This makes it possible to investigate scenarios not solvable with classical surface method of moments which assumes that good conductors as used. One practical example is the study of plasmonic devices whose operation relies on the interaction between material properties and radiation mechanisms. The implementation of the code is briefly summarized, including some implementation hints which allow for fast evaluation of necessary matrix operators. Two optimization problems are introduced and solved for scattering and antenna problems. Feasibility of the bounds will be investigated with topology optimization and the results will be presented during the conference.
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| 5. |
- Capek, Miloslav, et al.
(författare)
-
Inversion-Free Evaluation of Nearest Neighbors in Method of Moments
- 2019
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225. ; 18:11, s. 2311-2315
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Tidskriftsartikel (refereegranskat)abstract
- A recently introduced technique of topology sensitivity in method of moments is extended by the possibility of adding degrees of freedom (reconstruct) into the underlying structure. The algebraic formulation is inversion-free, suitable for parallelization, and scales favorably with the number of unknowns. The reconstruction completes the nearest neighbors procedure for an evaluation of the smallest shape perturbation. The performance of the method is studied with a greedy search over a Hamming graph representing the structure in which initial positions are chosen from a random set. The method is shown to be an effective data mining tool for machine learning-related applications.
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| 6. |
- Capek, Miloslav, et al.
(författare)
-
Inversion-free evaluation of small geometry perturbation in method of moments
- 2019
-
Ingår i: 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019 - Proceedings. - 9781728106922 ; , s. 1039-1040
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Konferensbidrag (refereegranskat)abstract
- Topology sensitivity is introduced and defined to be utilized within method of moments. It is based on a series of the smallest perturbations of the investigated structure and, thanks to the application of the Woodbury matrix identity, its evaluation is inversion-free, suitable for vectorization and parallelization, and results in a fast and versatile tool for analyzing antenna optimality.
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| 7. |
- Capek, Miloslav, et al.
(författare)
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Numerical Benchmark based on characteristic modes of a spherical shell
- 2017
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Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - 9781538632840 ; 2017-January, s. 965-966
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Konferensbidrag (refereegranskat)abstract
- Characteristic modes of a spherical shell are found analytically and compared with numerical solutions acquired from both in-house and commercial packages. These studies led to a proposal of several independent benchmarks, all with analytically known results. Dependence on mesh size, electrical size and other parameters can easily be incorporated. It is observed that all contemporary implementations have limitations.
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| 8. |
- Capek, Miloslav, et al.
(författare)
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Optimal Inverse Design Based on Memetic Algorithms - Part 1 : Theory and Implementation
- 2023
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 71:11, s. 8806-8816
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Tidskriftsartikel (refereegranskat)abstract
- A memetic framework for optimal inverse design is proposed by combining a local gradient-based procedure and a robust global scheme. The procedure is based on method-of-moments matrices and does not demand full inversion of a system matrix. Fundamental bounds are evaluated for all optimized metrics in the same manner, providing natural stopping criteria and quality measures for realized devices. Compared to density-based topology optimization, the proposed routine does not require filtering or thresholding. Compared to commonly used heuristics, the technique is significantly faster, still preserving a high level of versatility and robustness. This is a two-part paper in which the first part is devoted to the theoretical background and properties, and the second part applies the method to examples of varying complexity.
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| 9. |
- Capek, Miloslav, et al.
(författare)
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Optimal Inverse Design Based on Memetic Algorithms - Part II : Examples and Properties
- 2023
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 71:11, s. 8817-8829
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Tidskriftsartikel (refereegranskat)abstract
- Optimal inverse design, including topology optimization and evaluation of fundamental bounds on performance, which was introduced in Part 1, is applied to various antenna design problems. A memetic scheme for topology optimization combines local and global techniques to accelerate convergence and maintain robustness. Method-of-moments (MoMs) matrices are used to evaluate objective functions and allow determination of fundamental bounds on performance. By applying the Shermann-Morrison-Woodbury identity, the repetitively performed structural update is inversion-free yet full-wave. The technique can easily be combined with additional features often required in practice, e.g., only a part of the structure is controllable, or evaluation of an objective function is required in a subdomain only. The memetic framework supports multifrequency and multiport optimization and offers many other advantages, such as an actual shape being known at every moment of the optimization. The performance of the method is assessed, including its convergence and computational cost.
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| 10. |
- Capek, Miloslav, et al.
(författare)
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Optimal Planar Electric Dipole Antennas Searching for antennas reaching the fundamental bounds on selected metrics.
- 2019
-
Ingår i: IEEE Antennas & Propagation Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 1045-9243 .- 1558-4143. ; 61:4, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- Considerable time is often spent optimizing antennas to meet specific design metrics. Rarely, however, are the resulting antenna designs compared to rigorous physical bounds on those metrics. Here, we study the performance of optimized planar meander line antennas with respect to such bounds. Results show that these simple structures meet the lower bound on the radiation quality factor (Q-factor) (maximizing single-resonance fractional bandwidth) but are far from reaching the associated physical bounds for efficiency. The relative performance of other canonical antenna designs is comparable in similar ways, and the quantitative results are connected to intuitions from small antenna design, physical bounds, and matching network design.
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| 11. |
- Capek, Miloslav, et al.
(författare)
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Shape Synthesis Based on Topology Sensitivity
- 2019
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 67:6, s. 3889-3901
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Tidskriftsartikel (refereegranskat)abstract
- A method evaluating the sensitivity of a given parameter to topological changes is proposed within the method of moments paradigm. The basis functions are used as degrees of freedom which, when compared to the classical pixeling technique, provide important advantages, one of them being impedance matrix inversion free evaluation of the sensitivity. The devised procedure utilizes port modes and their superposition which, together with only a single evaluation of all matrix operators, leads to a computationally effective procedure. The proposed method is approximately 100 times faster than the contemporary approaches, which allows the investigation of the sensitivity and the modification of shapes in real time. The method is compared with the known approaches and its validity and effectiveness are verified using a series of examples. The procedure can be implemented in up-to-date electromagnetic (EM) simulators in a straightforward manner. It is shown that the iterative repetition of the topology sensitivity evaluation can be used for gradient-based topology synthesis. This technique can also be employed as a local step in global optimizers.
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| 12. |
- Capek, Miloslav, et al.
(författare)
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Unified Approach to Characteristic Modes
- 2021
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Ingår i: 2021 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting : APS/URSI 2021 - Proceedings - APS/URSI 2021 - Proceedings. - 9781728146706 ; , s. 893-894
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Konferensbidrag (refereegranskat)abstract
- An algebraic link between transition matrix and impedance matrix is utilized in this work to unify characteristic mode decomposition originally proposed by Garbacz with a framework proposed later on by Harrington and Mautz. The resulting formulation is unique to all method of moments formulations, valid for all linear and lossless materials, and has many favorable properties. The unified prescription is applicable to surface equivalence, body-of-revolution, or volumetric method of moments formulations. The unification paves a way to establish characteristic modes as a standalone technique in time-harmonic domain being independent of method of moment paradigm, i.e., to utilize - for example - finite element method instead.
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| 13. |
- Capek, Miloslav, et al.
(författare)
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Validating the Characteristic Modes Solvers
- 2017
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 65:8, s. 4134-4145
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Tidskriftsartikel (refereegranskat)abstract
- Characteristic modes (CMs) of a spherical shell are found analytically as spherical harmonics normalized to radiate unitary power and to fulfill specific boundary conditions. The presented closed-form formulas lead to a proposal of precise synthetic benchmarks that can be utilized to validate the method-of-moments matrix or performance of CM decomposition. Dependence on the mesh size, electrical size, and other parameters can systematically be studied, including the performance of various mode tracking algorithms. A notable advantage is the independence on feeding models. Both theoretical and numerical aspects of CM decomposition are discussed and illustrated by examples. The performance of state-of-the-art commercial simulators and academic packages having been investigated, we can conclude that all contemporary implementations are capable of identifying the first dominant modes while having severe difficulties with higher order modes. Surprisingly poor performance of the tracking routines is observed notwithstanding the recent ambitious development.
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| 14. |
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| 15. |
- Gustafsson, Mats, et al.
(författare)
-
Unified Theory of Characteristic Modes : Part I: Fundamentals
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; , s. 11801-11813
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Tidskriftsartikel (refereegranskat)abstract
- A unification of characteristic mode decomposition for all method-of-moment formulations of field integral equations describing free-space scattering is derived. The work is based on an algebraic link between impedance and transition matrices, the latter of which was used in early definitions of characteristic modes and is uniquely defined for all scattering scenarios. This also makes it possible to extend the known application domain of characteristic mode decomposition to any other frequency-domain solver capable of generating transition matrices, such as finite difference or finite element methods. The formulation of characteristic modes using a transition matrix allows for the decomposition of induced currents and scattered fields from arbitrarily shaped objects, providing high numerical dynamics and increased stability, removing the issue of spurious modes, and offering good control of convergence. This first part of a two-part paper introduces the entire theory, extensively discusses its properties and offers its basic numerical validation.
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| 16. |
- Gustafsson, Mats, et al.
(författare)
-
Unified Theory of Characteristic Modes : Part II - Tracking, Losses, and FEM Evaluation
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 70:12, s. 11814-11824
-
Tidskriftsartikel (refereegranskat)abstract
- This is the second component of a two-part paper dealing with a unification of characteristic mode decomposition. This second part addresses modal tracking, interpolation, the role of ohmic losses, and presents several numerical examples for surface-based method-of-moment formulations. A new tracking algorithm based on algebraic properties of the transition matrix is developed, achieving excellent precision and requiring a very low number of frequency samples as compared to procedures previously reported in the literature. The transition matrix is further utilized to show that characteristic mode decomposition of lossy objects fails to deliver orthogonal far fields and to demonstrate how characteristic modes can be evaluated using the finite element method.
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| 17. |
- Gustafsson, Mats, et al.
(författare)
-
Upper bounds on absorption and scattering
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A general framework for determining fundamental bounds in nanophotonics is introduced in this paper. The theory is based on convex optimization of dual problems constructed from operators generated by electromagnetic integral equations. The optimized variable is a contrast current defined within a prescribed region of a given material constitutive relations. Two power conservation constraints analogous to the optical theorem are utilized to tighten the bounds and to prescribe either losses or material properties. Thanks to the utilization of matrix rank-1 updates, modal decompositions, and model order reduction techniques, the optimization procedure is computationally efficient even for complicated scenarios. No dual gaps are observed. The method is well-suited to accommodate material anisotropy and inhomogeneity. To demonstrate the validity of the method, bounds on scattering, absorption, and extinction cross sections are derived first and evaluated for several canonical regions. The tightness of the bounds is verified by comparison to optimized spherical nanoparticles and shells. The next metric investigated is bi-directional scattering studied closely on a particular example of an electrically thin slab. Finally, the bounds are established for Purcell's factor and local field enhancement where a dimer is used as a practical example.
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| 18. |
- Gustafsson, Mats, et al.
(författare)
-
Upper bounds on absorption and scattering
- 2020
-
Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 22:7
-
Tidskriftsartikel (refereegranskat)abstract
- A general framework for determining fundamental bounds in nanophotonics is introduced in this paper. The theory is based on convex optimization of dual problems constructed from operators generated by electromagnetic integral equations. The optimized variable is a contrast current defined within a prescribed region of a given material constitutive relations. Two power conservation constraints analogous to the optical theorem are utilized to tighten the bounds and to prescribe either losses or material properties. Thanks to the utilization of matrix rank-1 updates, modal decompositions, and model order reduction techniques, the optimization procedure is computationally efficient even for complicated scenarios. No dual gaps are observed. The method is well-suited to accommodate material anisotropy and inhomogeneity. To demonstrate the validity of the method, bounds on scattering, absorption, and extinction cross sections are derived first and evaluated for several canonical regions. The tightness of the bounds is verified by comparison to optimized spherical nanoparticles and shells. The next metric investigated is bi-directional scattering studied closely on a particular example of an electrically thin slab. Finally, the bounds are established for Purcell's factor and local field enhancement where a dimer is used as a practical example.
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| 19. |
- Jelinek, Lukas, et al.
(författare)
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Fundamental bounds on the performance of monochromatic passive cloaks
- 2021
-
Ingår i: Optics Express. - 1094-4087. ; 29:15
-
Tidskriftsartikel (refereegranskat)abstract
- Fundamental bounds on the performance of monochromatic scattering-cancellation and field-zeroing cloaks made of prescribed linear passive materials occupying a predefined design region are formulated by projecting field quantities onto a sub-sectional basis and applying quadratically constrained quadratic programming. Formulations are numerically tested revealing key physical trends as well as advantages and disadvantages between the two classes of cloaks. Results show that the use of low-loss materials with high dielectric contrast affords the highest potential for effective cloaking.
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| 20. |
- Jelinek, Lukas, et al.
(författare)
-
Maximum Radiation Efficiency of Implanted Antennas Employing a Novel Hybrid Method
- 2021
-
Ingår i: 2021 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, APS/URSI 2021 - Proceedings. - 9781728146706 ; , s. 1339-1340
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Konferensbidrag (refereegranskat)abstract
- A hybrid combining T-matrix method and electric field integral equation is used to formulate fundamental bounds on radiation efficiency of an implanted antenna. Resulting quadratic optimization problem is solved using a dual formulation. The results present the versatility of the described computational scheme and show the optimal current densities that are the least impaired by dissipation in the tissue.
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| 21. |
- Losenicky, Vit, et al.
(författare)
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Dissipation Factors of Spherical Current Modes on Multiple Spherical Layers
- 2018
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 66:9, s. 4948-4952
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Tidskriftsartikel (refereegranskat)abstract
- Radiation efficiencies of modal current densities distributed on a spherical shell are evaluated in terms of dissipation factor. The presented approach is rigorous, yet simple and straightforward, leading to closed-form expressions. The same approach is utilized for a two-layered shell and the results are compared with other models existing in the literature. Discrepancies in this comparison are reported and reasons are analyzed. Finally, it is demonstrated that radiation efficiency potentially benefits from the use of internal volume which contrasts with the case of the radiation Q-factor.
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| 22. |
- Losenicky, Vit, et al.
(författare)
-
Method of Moments and T-Matrix Hybrid
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 70:5, s. 3560-3574
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid computational schemes combining the advantages of a method of moments formulation of a field integral equation and T-matrix method are developed in this article. The hybrid methods are particularly efficient when describing the interaction of electrically small complex objects and electrically large objects of canonical shapes such as spherical multilayered bodies where the T-matrix method is reduced to the Mie series making the method an interesting alternative in the design of implantable antennas or exposure evaluations. Method performance is tested on a spherical multilayer model of the human head. Along with the hybrid method, an evaluation of the transition matrix of an arbitrarily shaped object is presented and the characteristic mode decomposition is performed, exhibiting fourfold numerical precision compared to conventional approaches.
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| 23. |
- Lundgren, Johan, et al.
(författare)
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Iterative Calculation of Characteristic Modes Using Arbitrary Full-Wave Solvers
- 2023
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225. ; 22:4, s. 799-803
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Tidskriftsartikel (refereegranskat)abstract
- An iterative algorithm is adopted to construct approximate representations of matrices describing the scattering properties of arbitrary objects. The method is based on the implicit evaluation of scattering responses from iteratively generated excitations. The method does not require explicit knowledge of any system matrices (e.g., stiffness or impedance matrices) and is well-suited for use with matrix-free and iterative full-wave solvers, such as FDTD (Finite-difference time-domain method), FEM (Finite element method), and MLFMA (Multilevel Fast Multipole Algorithm). The proposed method allows for significant speed-up compared to the direct construction of a full transition matrix or scattering dyadic. The method is applied to the characteristic mode decomposition of arbitrarily shaped obstacles of arbitrary material distribution. Examples demonstrating the speed-up and complexity of the algorithm are studied with several commercial software packages.
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| 24. |
- Schab, Kurt, et al.
(författare)
-
Characteristic Modes of Frequency-Selective Surfaces and Metasurfaces from S-Parameter Data
- 2023
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 71:12, s. 9696-9706
-
Tidskriftsartikel (refereegranskat)abstract
- Characteristic modes of arbitrary 2-D periodic systems are analyzed using scattering parameter data. This approach bypasses the need for periodic integral equations and allows for characteristic modes to be computed from generic simulation or measurement data. Example calculations demonstrate the efficacy of the method through comparison against a periodic method of moments (MoM) formulation for a simple, single-layer conducting unit cell. The effect of vertical structure and electrical size on the number of modes is studied, and its discrete nature is verified with example calculations. A multiband polarization-selective surface and a beamsteering metasurface are presented as additional examples.
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| 25. |
- Schab, Kurt, et al.
(författare)
-
Energy Stored by Radiating Systems
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Though commonly used to calculate Q-factor and fractional bandwidth, the energy stored by radiating systems (antennas) is a subtle and challenging concept that has perplexed researchers for over half a century. Here, the obstacles in defining and calculating stored energy in general electromagnetic systems are presented from first principles as well as using demonstrative examples from electrostatics, circuits, and radiating systems. Along the way, the concept of unobservable energy is introduced to formalize such challenges. Existing methods of defining stored energy in radiating systems are then reviewed in a framework based on technical commonalities rather than chronological order. Equivalences between some methods under common assumptions are highlighted, along with the strengths, weaknesses, and unique applications of certain techniques. Numerical examples are provided to compare the relative margin between methods on several radiating structures.
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| 26. |
- Schab, Kurt, et al.
(författare)
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Energy Stored by Radiating Systems
- 2018
-
Ingår i: IEEE Access. - 2169-3536. ; 6, s. 10553-10568
-
Tidskriftsartikel (refereegranskat)abstract
- Though commonly used to calculate Q-factor and fractional bandwidth, the energy stored by radiating systems (antennas) is a subtle and challenging concept that has perplexed researchers for over half a century. Here, the obstacles in defining and calculating stored energy in general electromagnetic systems are presented from first principles as well as using demonstrative examples from electrostatics, circuits, and radiating systems. Along the way, the concept of unobservable energy is introduced to formalize such challenges. Existing methods of defining stored energy in radiating systems are then reviewed in a framework based on technical commonalities rather than chronological order. Equivalences between some methods under common assumptions are highlighted, along with the strengths, weaknesses, and unique applications of certain techniques. Numerical examples are provided to compare the relative margin between methods on several radiating structures.
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| 27. |
- Schab, Kurt, et al.
(författare)
-
Trade-offs in absorption and scattering by nanophotonic structures
- 2020
-
Ingår i: Optics Express. - 1094-4087. ; 28:24, s. 36584-36599
-
Tidskriftsartikel (refereegranskat)abstract
- Trade-offs between absorption and scattering cross sections of lossy obstacles confined to an arbitrarily shaped volume are formulated as a multi-objective optimization problem solvable by Lagrangian-dual methods. Solutions to this optimization problem yield a Pareto-optimal set, the shape of which reveals the feasibility of achieving simultaneously extremal absorption and scattering. Two forms of the trade-off problems are considered involving both pre-assigned loss and reactive material parameters. Numerical comparisons between the derived multi-objective bounds and several classes of realized structures are made. Additionally, low-frequency (electrically small, long wavelength) limits are examined for certain special cases.
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| 28. |
- Schab, Kurt, et al.
(författare)
-
Upper bounds on focusing efficiency
- 2022
-
Ingår i: Optics Express. - 1094-4087. ; 30:25, s. 45705-45723
-
Tidskriftsartikel (refereegranskat)abstract
- Upper bounds on the focusing efficiency of aperture fields and lens systems are formulated using integral equation representations of Maxwell’s equations and Lagrangian duality. Two forms of focusing efficiency are considered based on lens exit plane fields and optimal polarization currents within lens design regions of prescribed shape and available materials. Bounds are compared against the performance of classical prescriptions of ideal lens aperture fields, hyperbolic lens designs, and lenses produced by inverse design. Results demonstrate that, without regularization, focusing efficiency based solely on lens exit plane fields is unbounded, similar to the problem of unbounded antenna directivity. Additionally, results considering extruded two-dimensional dielectric geometries driven by out-of-plane electric fields for the calculation of bounds and inverse design demonstrate that aperture fields based on time-reversal do not necessarily yield optimal lens focusing efficiency, particularly in the case of near-field (high numerical aperture) focusing.
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| 29. |
- Tayli, Doruk, et al.
(författare)
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Accurate and Efficient Evaluation of Characteristic Modes
- 2018
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 66:12, s. 7066-7075
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Tidskriftsartikel (refereegranskat)abstract
- A new method to improve the accuracy and efficiency of characteristic mode (CM) decomposition for perfectly conducting bodies is presented. The method uses the expansion of the Green dyadic in spherical vector waves. This expansion is utilized in the method of moments (MoM) solution of the electric field integral equation (EFIE) to factorize the real part of the impedance matrix. The factorization is then employed in the computation of CMs, which improves the accuracy as well as the computational speed. An additional benefit is a rapid computation of far fields. The method can easily be integrated into existing MoM solvers. Several structures are investigated illustrating the improved accuracy and performance of the new method.
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| 30. |
- Tayli, Doruk, et al.
(författare)
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Accurate and Efficient Evaluation of Characteristic Modes
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A new method to improve the accuracy and efficiency of CM decomposition for perfectly conducting bodies is presented. The method uses the expansion of the Green dyadic in spherical vector waves. This expansion is utilized in the MoM solution of the EFIE to factorize the real part of the impedance matrix. The factorization is then employed in the computation of CM, which improves the accuracy as well as the computational speed. An additional benefit is a rapid computation of far fields. The method can easily be integrated into existing MoM solvers. Several structures are investigated illustrating the improved accuracy and performance of the new method.
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