KTH regulations: This is a personal web page created by Lars Jonsson. More information. You can contact me at ljonsson AT kth DOT se.

BLG Jonsson's current research projects and interests and publications:

• Antennas, scattering and coupling Antennas and electromagnetic scattering is two quite wide and very interesting subjects. One remarkable result is the recently derived fundamental limitations on antennas which are based in a scattering perspective. These sum-rule results are a new and interesting research area. In addition to these more fundamental behavior, we have recently studied several configurations of antenna and antenna scattering including curvilinear radomes, element position perturbations for the design of satellite antennas. As well as problems around communication antennas. In 2013 we discovered the array figure of merit that connects bandwidth, reflection coefficient, scan-range and structural parameters. It is a size-independent way to compare and to predict e.g. bandwidth behavior for array antennas over a ground plane. This research is tightly coupled with mathematical knowledge, and hence with the 2014-2019 SSF project on applied mathematics. The work on the array antennas has resulted in a best student paper for my PhD student Christos Kolitsidas. Over the last few years we have also studied stored energies for antennas, with the goal to bound the quality factor of small antennas, see Stored energies. Q-based bounds on periodic arrays has been derived and published 2019-2021.

  Another set of works under this headline also includes direction of arrival with H. Frid, MIMO-cubes and energy harvesting with C. Kolitsidas and B. Mouris. A fun and useful tool in the context of arrays is the recently developed visualization of mutual coupling, 2018, 2021, 2022.

• Materials and scattering Nanocomposites materials have been suggested in several disciplines, with frequency ranging from DC to optical. My interest here are within dielectric nanocomposites, with applications as insulation materials. This is a new and exciting area, and there is a range of fundamental effects to examine and understand. For strong electric fields nonlinear effects appear to complicate the picture. The interaction between the nanoparticles/media and the field is a form of low-frequency scattering in Power applications.

• Inverse scattering problems (Linear hyperbolic equations), wave field decomposition in anisotropic media. Field reconstruction in connection with specific absorption rate in the human body (SAR)
  

• Soliton dynamics and Solitary waves dynamics (Hamiltonian systems): Efficient dynamics for solitons (and solitary waves) for generalized nonlinear Schrödinger equations with potentials and for Maxwell's equations with nonlinear constitutive relations. My research interests also includes: many solitary waves interaction, blow-up phenomena, polarization. Semi-relativistic Hartree equation, also called pseudo-relativistic Hartree equation which models boson stars. Nonlinear optics with applications.
  

• Time reversal and retrofocusing (linear acoustic and electromagnetic fields) Retrofocusing of Acoustic Wave Fields by Iterated Time Reversal Acoustic time-reversal mirrors in the framework of one-way theories.
  

Scientific papers/book chapters

2021-2025

• H. Hultin, Åkerstedt, B. L. G. Jonsson, Solver Performance of Accelerated MoM for Connected Arrays, ArXiv 2506.20350, p1-11, June 2025
• L Åkerstedt, H. Hultin, B. L. G. Jonsson, An Array Decomposition Method for Finite Arrays with Electrically Connected Elements for fast Toeplitz Solvers, ArXiv 2506.04710, p1-12, June 2025
• L. Åkerstedt, D. Blanco, B. L. G. Jonsson, On Adaptive Frequency Sampling for Data-driven Model Order Reduction Applied to Antenna Responses, IEEE Transactions on Antennas and Propagation, 73(8) pp 5741-5750, Aug. 2025, see also ArXiV: 2409.18734, p1--10, 2024. For an implementation see also: example.
• H. Frid, H. Hultin, B. L. G. Jonsson, Convex Optimization of Wideband Monopulse Arrays, IEEE Transactions on Antennas and Propagation, 72(5) pp. 4246-4257, March 2024
• A. Emadeddin, B. L. G. Jonsson, A Fully Integrated Filtering Vivaldi Antenna with High Selectivity and Wide Out-of-Band Suppression, IEEE Access, vol. 12 pp2690--2700, Jan. 2024
• A. Emadeddin, B. L. G. Jonsson, Coupling Reduction in an Active Highly-Integrated Tx Phased Array Antenna with Scanning Capability, AUE - International Journal of Electronics and Communications, 169(154717), 2023.
• A. Emadeddin, B. L. G. Jonsson, Wide Scan, Active K-band, Direct-Integrated Phased Array for Efficient High-Power Tx-Generation, IEEE Transactions on Antennas and Propagation 71(9) pp 7579--7584, Sept. 2023, see also TechRxiv.
• J. Lundgren, J. Malmström, J.-M. Hannula, B. L. G. Jonsson, Visualization and Reduction of Mutual Coupling Between Antennas Installed on a Platform, IEEE Transactions on Electromagnetic Compatibility, 64(1) pp. 92.101, 2022, See also: Techrxiv 2020-11-18
• A. Ludvig-Osipov, J.-M. Hannula, P. Naccachian, B. L. G. Jonsson, Physical limitations of phased array antennas, IEEE Transactions on Antennas and Propagation 69(9) pp. 5512-5523, Sept. 2021, See also: ArXiv:2006.02777, from Jun. 2020.
• B. L. G. Jonsson, F. Ferrero, S. Shi, and L. Wang, Optimal Bandwidth Positions for a Terminal Embedded Antenna: Physical Bounds and Antenna Design, IEEE Transactions on Antennas and Propagation, 69(4) pp 1931-1941, 2021.

  2016-2020

• A. Ludvig-Osipov, B. L. G. Jonsson, Q-factor and bandwidth of periodic antenna arrays over ground plane, IEEE Antennas and Wireless Propagation Letters, 19(1) pp. 158-162, Jan. 2020. See also ArXiv 1909.08019.
• H. Frid, J. Malmström, B. L. G. Jonsson, Determining Direction-of-Arrival Accuracy for Installed Antennas by Post-Processing of Far-Field Data, Radio Science 54(12), pp. 1171--1251, Nov. 2019.
• O. Zetterström, C. I. Kolitsidas, B. L. G. Jonsson, A. A. Glazunov, A 28-port MIMO Cube for Micro Base Station Application, IEEE Transactions on Antennas and Propagation, 68(5), pp. 3443-3452, May. 2020.
• A. Ludvig-Osipov, B. L. G. Jonsson, Stored energies and Q-factor of two-dimensionally periodic antenna arrays, IEEE Transactions on Antennas and Propagation, 68(8), pp. 5989-6002, 2020, see also ArXiv 1903.01494
• B. A. Mouris, H. Ghauch, R. Thobaben, B. L. G. Jonsson, Multi-tone Signal Optimization for Wireless Power Transfer in the Presence of Wireless Communication Links, IEEE Transactions on Wireless Communications, 19(5) pp. 3575-3590, May, 2020, see also ArXiv
• Y. Ivanenko, M. Nedic, M. Gustafsson, B. L. G. Jonsson, A. Luger, S. Nordebo, Quasi-Herglotz functions and convex optimization, Royal Society Open Science, 7(1) pp. 1--15, 2020. See also ArXiv 1812.08319.
• A. Ludvig-Osipov, J. Lundgren, C. Ehrenborg, Y. Ivanenko, A. Ericsson, M. Gustafsson, B. L. G. Jonsson, D. Sjöberg, Fundamental bounds on transmission through periodically perforated metal screens with experimental validation, IEEE Transactions on Antennas and Propagation, 68(2) pp. 773-782, 2020. See also ArXiv 1810.07669
• M. Capek, L. Jelinek, K. Schab, M. Gustafsson, B. L. G. Jonsson, F. Ferrero, C. Ehrenborg, Optimal Planar Electric Dipole Antennas: Searching for antennas reaching the fundamental bounds on selected metrics, IEEE Antennas and Propagation Magazine, 61(4), pp. 19--29 Aug. 2019, See also ArXiv 1808.10755
• S. Shi, L. Wang, B. L. G. Jonsson, Antenna Current Optimization and Optimization for Far-Field Pattern Shaping, ArXiv 1711.09709v2, Aug. 2018
• A. Ludvig-Osipov, B. L. G. Jonsson, Evaluation of the Electric Polarizability for Planar Frequency Selective Arrays, IEEE Antennas and Wireless Propagation Letters, 17(7) pp1158--1161, May 2018, see also:ArXic 1711.10437
• O. Mattsson, C. I. Kolitsidas, B. L. G. Jonsson, Dual Band Dual Polarized Full Wave Rectenna Based on Differential Field Sampling, IEEE Antennas and Wireless Propagation Letters, 17(6), 956-959, April, 2018
• Y. Ivanenko, M. Gustafsson, B. L. G. Jonsson, A. Luger, B. Nilsson, S. Nordebo, J. Toft: Passive approximation and optimization using B-splines, SIAM J Appl Math. 79(1) pp. 436--458 Jan. 2019. See also ArXiv 1711.07937.
• J. Malmström, H. Holter, B. L. G. Jonsson:On Mutual Coupling and Coupling Paths between Antennas Using the Reaction Theorem, IEEE Transactions on Electromagnetic Compatibility 60(6), pages 2037--2040, 2018.
• P. I. Bantavis, C. I. Kolitsidas, T. Empliouk, M. Le Roy, B. L. G. Jonsson, G. A. Kyriacou: A Cost-effective Wideband Switched Beam Antenna System for a Small Cell Base Station , IEEE Transaction on Antennas and Propagation, 66(12) pp 6851-6861, 2018.
• M. Nedic, C. Ehrenborg, Y. Ivanenko, A. Ludvig-Osipov, S. Nordebo, A. Luger, B. L. G. Jonsson, D. Sjöberg, and M. Gustafsson: Herglotz functions and applications in electromagnetics, Book title: Advances in Mathematical Methods for Electromagnetics, Editors K. Kobayashi and P. Smith, Publ. Institution of Engineering and Technology (IET), ISBN: 9781785613845, Chapter 20, Pages 491--514, 2021
• O. Björkqvist, O. Dahlberg, G. Silver, C.I. Kolitsidas, O. Quevedo-Teruel, B. L. G. Jonsson, Wireless Sensor Network Utilizing Radio-Frequency Energy Harvesting for Smart Building Applications, 8 pages, Best student paper award, IEEE Antennas and Propagation Magazine, 60(5), pp: 124-136, 2018.
• C. I. Kolitsidas, P. I. Bantavis, B. L. G. Jonsson, G. A. Kyriacou, "The Soft Vivaldi Antenna Array with an Integrated Matching Layer", Dec 2017. In PhD-thesis of C. I. Kolitsidas, 2017.
• C. I. Kolitsidas, B. L. G. Jonsson:The strongly coupled asymmetric dipole array (SCADA) with an E-plane edge termination, October 2017. In PhD-thesis of C. I. Kolitsidas, 2017.
• F. Ferrero, L. Lizzi, B. L. G. Jonsson, L. Wang, A Two-element Parasitic Antenna Approaching the Minimum Q-factor at a Given Directivity, ArXiv 1705.02281, 11 pages. May 2017
• J. Malmström, H. Holter, B. L. G. Jonsson, On the Accuracy of Equivalent Antenna Representations, IEEE Transaction on Antennas and Propagation, 66(7), pp3251--3260, 2018. See also ArXiv1701.03275
• B. L. G. Jonsson, S. Shi, L. Wang, F. Ferrero, L. Lizzi, On Methods to determine bounds on the Q-factor for a given directivity, IEEE Transactions of Antennas and propagation 65(11) pp 5686--5696, 2017, ArXiv:1702.03234, 8 pages, Feb 2017.
• E. Kubyshkina, M. Unge, B. L. G. Jonsson, Band bending at the interface in Polyethylene-MgO nanocomposite dielectric, The Journal of Chemical Physics 146, 051101 (2017), see also ArXiv 1611.10251,
• B. L. G. Jonsson, M. Gustafsson, Stored energies for electric and magnetic current densities, ArXiv 1604.08572, 25 pages, 2016

  2011-2015

• M. Gustafsson, B. L. G. Jonsson, Stored electromagnetic energy and antenna Q, Progress in Electromagnetic Research 150, pages 13-27, 2015.
• B. L. G. Jonsson, M. Gustafsson, Stored energies in electric and magnetic current densities for small antennas, Royal Society of London, Proceedings A. Vol. 471(2176) pp. 1-23, 2015, see also, ArXiv 1210.8074, pages 1--27, 2014.
• H. Frid, H. Holter and B. L. G. Jonsson: An Approximate Method for Calculating the Near-Field Mutual Coupling between Antennas on Vehicles IEEE Transactions on Antennas and Propagation, 63(9) pp 4132-4138, 2015.
• M. Gustafsson, B. L. G. Jonsson, Antenna Q and stored energy expressed in the fields, currents, and input impedance , IEEE Transactions on Antennas and Propagation, 63(1) 240-249, 2015.
• D. Colombi, B. Thors, B. L. G. Jonsson: Efficient whole-body SAR assessments by means of surface scan measurements IEEE Transactions on Electromagnetic Compatibility, 56(3) 2014.
• A. D. Yaghjian, M. Gustafsson, B. L. G. Jonsson, Minimum Q for lossy and lossless electrically small dipole antennas, Progress in Electromagnetics Research 143, pages 641--673, 2013.
• B. L. G. Jonsson, C. I. Kolitsidas, N. Hussain, Array Antenna Limitations, IEEE Antennas and Wireless Propagation Letters, 12(1) pp.1539--1542, 2013, 1307.2925.
• M. Gustafsson, B. L. G. Jonsson, Stored Electromagnetic Energy and Antenna Q, ArXiv:1211.5521 pages 1-31, 2013.
• A. Motevasselian, A. Ellgardt, B. L. G. Jonsson, A Helix Excited Circularly Polarized Hollow Cylindrical Dielectric Resonator Antenna IEEE Antennas and Wireless Propagation Letters 12, pp 535--538, 2013.
• B. Venkatesulu, B. L. G. Jonsson, H. Edin, M. Norgren Modeling of Insulating Nanocomposites-Electric and Temperature Fields IEEE Transactions on Dielectrics and Electrical Insulation 20(1) pages 177--184, 2013.
• A. Motevasselian, A. Ellgardt, B. L. G. Jonsson: A Circularly Polarized Cylindrical Dielectric Resonator Antenna Using a Helical Exciter. IEEE Transactions on Antennas and Propagation 61(3) pages 1439--1443, 2013
• M. Gustafsson, M. Cismasu, B. L. G. Jonsson: Physical Bounds and Optimal Currents on Antennas IEEE Transactions on Antennas and Propagation 60(6) p2672--2681, 2012.
• A. Motevasselian, B. L. G. Jonsson: Design of a Wideband Absorber with a Polarization Sensitive Transparent Window, IET Microwave Antennas Propagation, 6(7), p.747--755 2012
• B. L. G. Jonsson, Yu. N. Ovchinnikov, I. M. Sigal, F. S. T. Ting: Dynamics of breakup of multiple vortices in Gross-Pitaevskii equations of superfluids, Journal of Mathematical Physics vol 50, 093505 16 pages, 2011. The article was also selected to appear in the October 2011 issue of Virtual Journal of Atomic Quantum Fluids vol 3(10) 2011.
  
• A. Motevasselian, B. L. G. Jonsson: Partially Transparent Jaumann Like Absorber Applied to a Curved Structure, International Journal of Antennas and Propagation Vol 2011, Article ID 708987, 7 pages, 2011
  

  Papers 2010 and earlier

• W. Bukhsh, B. L. G. Jonsson, P. Persson: Element position perturbation for a narrow spot beam with applications to satellite communication antennas. Progress in Electromagnetic Research, 104, pp. 283--295, 2010.
  
• B. L. G. Jonsson, M. Norgren: Asymptotic wave-splitting in anisotropic linear acoustics, Wave Motion, 47(5), pp. 318-326, 2010, see also arXiv:math-ph/0908.1507
  
• M. Norgren, B. L. G. Jonsson: The capacitance of the circular parallel plate capacitor obtained by solving the Love integral equation using an explicit expansion of the kernel, PIER 97, pp 357-372, 2009.
  
• V. Bach, J. Fröhlich and B. L. G. Jonsson: Bogolubov-Hartree-Fock Mean Field Theory for Neutron Stars and other Systems with Attractive Interactions , J. Math. Phys. 50, 102102 (22 pages), 2009. See also Texas_08-243.
  
• L. Fishman, B. L. G. Jonsson and M. V. de Hoop: Time Reversal Mirrors and Cross Correlation Functions in Acoustic Wave Propagation, Mathematical Modeling of Wave Phenomena: 3rd Conference on Mathematical Modeling of Wave Phenomena, 20th Nordic Conference on Radio Science and Communications; AIP Conf. Proc. Volume 1106, pp. 183-203 March 24, 2009
  
• B. L. G. Jonsson: The kernel condition of a linearized pseudo-relativistic Hartree equation, a numerical approach, Mathematical Modeling of Wave Phenomena: 3rd Conference on Mathematical Modeling of Wave Phenomena, 20th Nordic Conference on Radio Science and Communications; AIP Conf. Proc. Volume 1106, pp. 173-180, March 24, 2009
  
• B. L. G. Jonsson: Wave splitting of Maxwell's equations with anisotropic heterogeneous constitutive relations, Inverse Problems and Imaging 3(2), pp 405-452, 2009. ArXiv:math-ph/0809.0789v1.
  
• J. Fröhlich, B. L. G. Jonsson, E. Lenzmann: Effective Dynamics for Boson Stars, Nonlinearity, 20, pp1031--75, 2007 ArXiv:math-ph/0503009, Texas:06-162.
  
• J. Fröhlich, B. L. G. Jonsson, E. Lenzmann: Boson Stars as Solitary Waves, Comm. Math. Phys. Feb. 274(1), pp1--30, 2007. ArXiv:math-ph/0503009, Texas:05-417.
  
• B. L. G. Jonsson, J. Fröhlich, S. Gustafson, I. M. Sigal: Long Time Motion of NLS Solitary Waves in a Confining Potential, Annales Henri Poincare, 7(4), pp621--660, 2006.
  
• S. Dejak, B. L. G. Jonsson: Long-Time Dynamics of Variable Coefficient mKdV Solitary Waves, J. Math. Phys 47, 072703 pp. 1--16, 2006
  
• J. Fröhlich, S. Gustafson, B. L. G. Jonsson, I. M. Sigal: Solitary Wave Dynamics in an External Potential, Comm., Math. Phys. 250(3), pp.613--642, 2004.
  
• B. L. G. Jonsson, M. Gustafsson, V. H. Weston and de Hoop: Retrofocusing of Acoustic Wave Fields by Iterated Time Reversal: SIAM J. of Appl. Math. 64(6), pp. 1954--1986, 2004.
  
• B. L. G. Jonsson, Explicit solitary-wave ground state in one dimension", Texas Archive 04-153. 2004. PDF
  
• V. H. Weston and B. L. G. Jonsson: Wave front layer stripping approach to inverse scattering for the wave equation: J. Math. Phys. 43(10), pp. 5045--5059. 2002.
  
• B. L. G. Jonsson and M. V. de Hoop: Wave Field Decomposition in Anisotropic Fluids: A Spectral Theory Approach Acta Appl. Math. 67(2) pp. 117--171. June 2001.
  
• B. L. G. Jonsson: Directional Decomposition in Anisotropic Heterogeneous Media for Acoustic and Electromagnetic Fields, at Royal Institute of technology (You can access my thesis at KTH's online library: Thesis). March 2001.

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  Names -- my name is Lars, however both Lars and Jonsson are common names here, and hence I prefer to publish using the initials to my complete name: B. L. G. Jonsson.

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