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Publications (10 of 39) Show all publications
Kalaran, H., Karlsson, K., Moestam, R., Bergqvist, B. & Rosdalen, Å. (2022). Eigenmodes of a Loaded Reverberation Chamber. In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 212-215: . Paper presented at 2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022 (pp. 212-215). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Eigenmodes of a Loaded Reverberation Chamber
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2022 (English)In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 212-215, Institute of Electrical and Electronics Engineers Inc. , 2022, p. 212-215Conference paper, Published paper (Refereed)
Abstract [en]

The analytical solution for a loaded reverberation chamber has been investigated. In consistence with earlier works, it is shown that adding a dielectric (non-absorbing) into the chamber will reduce the eigenfrequency of the chamber. This can be a step toward lowering usable frequency inside the Reverberation Chamber and representing the modes density similarly to an empty chamber.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
analytical solution, loaded reverberation chamber, lowest usable frequency, Anechoic chambers, Electromagnetic compatibility, Eigen modes, Eigenfrequency, Low usable frequency, Mode density, Reverberation chambers, Reverberation
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-61238 (URN)10.1109/EMCEurope51680.2022.9901135 (DOI)2-s2.0-85140204231 (Scopus ID)9781665407878 (ISBN)
Conference
2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022
Note

Funding details: VINNOVA; Funding text 1: The work presented in this paper is carried out within the FFI EMCVERA project, which is partly funded by the Swedish government via VINNOVA.

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2023-05-25Bibliographically approved
Karlsson, K., Moestam, R., Bergqvist, B., Kalaran, H. & Rosdalen, Å. (2022). Electrical Fields in Vehicular Cavities During Reverberation Chamber EMC Immunity Test. In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 189-194: . Paper presented at 2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022 (pp. 189-194). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Electrical Fields in Vehicular Cavities During Reverberation Chamber EMC Immunity Test
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2022 (English)In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 189-194, Institute of Electrical and Electronics Engineers Inc. , 2022, p. 189-194Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we elaborate on EMC immunity tests in reverberation chambers of full-sized vehicles as well as these products' corresponding electromagnetic susceptibility. It is described how vehicles have regions or volumes (i.e., cavities), with sometimes installed hardware as well as software, which potentially is susceptible to electromagnetic interference, and how these cavities during test have properties (deterministic to ergodic) implying frequency-dependent properties of the electrical fields. Number of degrees of freedom for the electric fields is used to explain the behaviour of EMC, from deterministic coherent resonances and all the way to ergodic regions. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
cavity, EMC, immunity, reverberation chamber, vehicle, Anechoic chambers, Degrees of freedom (mechanics), Electric fields, Electromagnetic pulse, Magnetic susceptibility, Reverberation, Software testing, Vehicles, Deterministics, Electrical field, Electromagnetic susceptibilities, Ergodics, Frequency-dependent, Immunity test, Property, Reverberation chambers, Electromagnetic compatibility
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-61236 (URN)10.1109/EMCEurope51680.2022.9900992 (DOI)2-s2.0-85140240958 (Scopus ID)9781665407878 (ISBN)
Conference
2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022
Note

 Funding details: VINNOVA; Funding text 1: ACKNOWLEDGMENT The work presented in this paper is carried out within the FFI EMCVERA project, which is partly funded by the Swedish government via VINNOVA.

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2023-05-25Bibliographically approved
Karlsson, K., Lundberg, A., Arabäck, N. & Bergqvist, B. (2022). Test Level in Reverberation Chamber EMC Immunity Assessment Based on the Quantile to Average Ratio. In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 178-182: . Paper presented at 2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022 (pp. 178-182). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Test Level in Reverberation Chamber EMC Immunity Assessment Based on the Quantile to Average Ratio
2022 (English)In: IEEE International Symposium on Electromagnetic Compatibility. Volume 2022-September, 2022, Pages 178-182, Institute of Electrical and Electronics Engineers Inc. , 2022, p. 178-182Conference paper, Published paper (Refereed)
Abstract [en]

As more and more advanced electronics are incorporated into devices and vehicles, there is a need to improve and refine the test methods for performance assessment of electromagnetic compatibility. Traditional standards in reverberation chamber electromagnetic compatibility immunity assessment define the test level according to a calibration based on an average of maximum received electrical field probe readings. In this paper, we propose a converging approach based on the average, in combination with an additional offset to generate a quantile defined test level. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
calibration, EMC, immunity, quantile, reverberation chamber, Anechoic chambers, Reverberation, Testing, Advanced Electronics, Electrical field, Field probes, Performance assessment, Reverberation chambers, Test levels, Test method, Electromagnetic compatibility
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-61237 (URN)10.1109/EMCEurope51680.2022.9901226 (DOI)2-s2.0-85140222497 (Scopus ID)9781665407878 (ISBN)
Conference
2022 International Symposium on Electromagnetic Compatibility - EMC Europe, EMC Europe 2022, 5 September 2022 through 8 September 2022
Note

 Funding details: VINNOVA; Funding text 1: The work presented in this paper is carried out within the FFI EMCVERA project, which is partly funded by the Swedish government via VINNOVA.

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2024-06-24Bibliographically approved
Patane Lotback, C. S., Karlsson, K., Kildal, M. S., Haliti, A., Nilsson, M. & Iustin, R. (2021). Evaluation of Complete Vehicle Over-The-Air Verification Methods for Multiple-Input Multiple-Output Communication Systems. In: 15th European Conference on Antennas and Propagation, EuCAP 2021: . Paper presented at 15th European Conference on Antennas and Propagation, EuCAP 2021, 22 March 2021 through 26 March 2021. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Evaluation of Complete Vehicle Over-The-Air Verification Methods for Multiple-Input Multiple-Output Communication Systems
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2021 (English)In: 15th European Conference on Antennas and Propagation, EuCAP 2021, Institute of Electrical and Electronics Engineers Inc. , 2021Conference paper, Published paper (Refereed)
Abstract [en]

As more and more advanced wireless technologies are incorporated into vehicles, there is a need to refine the test methods used for assessing the performance. Traditional test setups for multiple-input multiple-output (MIMO) communication systems have been developed for relatively small devices such as handsets and tablets. At the same time, there is a desire to replace vehicular field tests with lab testing, for more efficient and accurate testing. This paper evaluates over-the-air verification methods for MIMO communication systems, which may incorporate vehicle-sized antenna systems and that can be implemented in a lab. Different methods are compared by means of a round robin campaign. The results from the campaign indicate that performance assessment representative to real-world operation can be achieved.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2021
Keywords
Anechoic chamber, cellular communication, MIMO, over-the-air, random line-of-sight (LOS), reverberation chamber, vehicle-to-everything (V2X), vehicular communication, Antennas, Feedback control, Telecommunication repeaters, Testing, Vehicles, Accurate testing, Antenna system, MIMO communication system, Multiple-input multiple-output communication systems, Performance assessment, Real world operations, Verification method, Wireless technologies, MIMO systems
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-53136 (URN)10.23919/EuCAP51087.2021.9410996 (DOI)2-s2.0-85105434667 (Scopus ID)9788831299022 (ISBN)
Conference
15th European Conference on Antennas and Propagation, EuCAP 2021, 22 March 2021 through 26 March 2021
Note

Funding details: VINNOVA; Funding text 1: The work presented in this paper is carried out within the FFI SIVERT project, which is partly founded by the Swedish government via VINNOVA. The authors want to further thank Bluetest AB, who provided the reference antennas used for the measurements in this study.

Available from: 2021-05-26 Created: 2021-05-26 Last updated: 2023-05-25Bibliographically approved
Karlsson, K., Wersäll, M., Harrysson, F. & Patane Lotback, C. S. (2021). On the Keyhole Effect in Over-The-Air Testing of Higher Order MIMO Systems. In: 15th European Conference on Antennas and Propagation, EuCAP 2021: . Paper presented at 15th European Conference on Antennas and Propagation, EuCAP 2021; Dusseldorf; Germany; 22 March 2021 through 26 March 20211. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>On the Keyhole Effect in Over-The-Air Testing of Higher Order MIMO Systems
2021 (English)In: 15th European Conference on Antennas and Propagation, EuCAP 2021, Institute of Electrical and Electronics Engineers Inc. , 2021Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, the influence of a limited number of radio frequency connections between two Rayleigh fading environments, also known as the keyhole effect, is theoretically investigated for higher-order MIMO systems. It is shown that the effect of a limited number of keyholes is kept stable or is even reduced as the number of keyholes is equal to or larger than the MIMO system order. The results are relevant for over-the-air testing with connected Rayleigh fading systems, such as a channel emulator connected to a reverberation chamber, or a reverberation chamber connected to another reverberation chamber (nested reverberation chambers).

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2021
Keywords
Channel emulator, keyhole effect, MIMO, nested, over-the-air, reverberation chamber, Anechoic chambers, MIMO systems, Rayleigh fading, Channel emulators, Fading environment, Higher-order, Keyhole effects, Nested reverberation chambers, Over the airs, Radio frequencies, Reverberation chambers, Reverberation
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-53137 (URN)10.23919/EuCAP51087.2021.9410976 (DOI)2-s2.0-85105502094 (Scopus ID)9788831299022 (ISBN)
Conference
15th European Conference on Antennas and Propagation, EuCAP 2021; Dusseldorf; Germany; 22 March 2021 through 26 March 20211
Note

 Funding details: VINNOVA; Funding text 1: This work has been financed by the Swedish government agency for innovation systems (VINNOVA) within the Sivert project.

Available from: 2021-05-26 Created: 2021-05-26 Last updated: 2023-05-25Bibliographically approved
Nagalapur, K. K., Ström, E. G., Brännström, F., Carlsson, J. & Karlsson, K. (2020). Robust Connectivity With Multiple Directional Antennas for Vehicular Communications. IEEE transactions on intelligent transportation systems (Print), 21(12), 5305-5315
Open this publication in new window or tab >>Robust Connectivity With Multiple Directional Antennas for Vehicular Communications
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2020 (English)In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 21, no 12, p. 5305-5315Article in journal (Refereed) Published
Abstract [en]

For critical vehicular communication services, such as traffic safety and traffic efficiency, it is advisable to design systems with robustness as the main criteria, possibly at the price of reduced peak performance and efficiency. We describe a simple, low-cost method for combining the output of L directional (i.e., not omnidirectional) antennas to the input of a single-port receiver with the aim to guarantee robustness, i.e., to minimize the probability that K consecutive packets arriving from the worst-case angle-of-arrival are decoded incorrectly. To minimize complexity, the combining network does not estimate or use channel state information. The combining network consists of L-1 analog phase shifters whose phases are affine functions of time. For a general Lłe K and when the packet error probability decays exponentially with the received SNR, the optimum slopes of the affine functions can be computed by solving an optimization problem that depends on the antenna far-field functions. We provide analytical solutions for the special case of L=2 and 3 antennas, which turns out to be independent of the antenna far-field functions and placement on a vehicle. In an experimental setup consisting of two monopole antennas mounted on the roof of a Volvo XC90, the proposed combining method is shown to give significant performance gains, compared to using any one of the antennas.

Keywords
Receiving antennas, Robustness, Signal to noise ratio, Transmitters, Antenna accessories, vehicular communications, burst error probability, directional antennas, analog combining network.
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-42575 (URN)10.1109/TITS.2019.2956099 (DOI)
Available from: 2020-01-10 Created: 2020-01-10 Last updated: 2023-05-25Bibliographically approved
Ji, Y., Fan, W., Nilsson, M., Hentila, L., Karlsson, K., Tufvesson, F. & Pedersen, G. (2020). Virtual Drive Testing Over-the-Air for Vehicular Communications. IEEE Transactions on Vehicular Technology, 69(2), 1203-1213, Article ID 8917696.
Open this publication in new window or tab >>Virtual Drive Testing Over-the-Air for Vehicular Communications
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2020 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 69, no 2, p. 1203-1213, article id 8917696Article in journal (Refereed) Published
Abstract [en]

Multiple-input multiple-output (MIMO) over-the-air (OTA) testing is a standardized procedure to evaluate the performance of MIMO-capable devices such as mobile phones and laptops. With the growth of the vehicle-to-everything (V2X) service, the need for vehicular communication testing is expected to increase significantly. The so-called multi-probe anechoic chamber (MPAC) setup is standardized for MIMO OTA testing. Typically, a test zone of 0.85 wavelength in diameter can be achieved with an 8-probe MPAC setup, which can encompass device-under-test (DUT) of small form factors. However, a test zone of this size may not be large enough to encompass DUTs such as cars. In this article, the sufficient number of OTA probes for the MPAC setup for car testing is investigated with respect to the emulation accuracy. Our investigation shows that the effective antenna distance of the DUT is more critical than its physical dimensions to determine the required number of OTA probes. In addition, throughput measurements are performed under the standard SCME UMa and UMi channel models with the 8-probe MPAC setup and the wireless cable setup, i.e. another standardized testing setup. The results show reasonably good agreement between the two setups for MIMO OTA testing with cars under the standard channel models. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2020
Keywords
and wireless cable, channel modeling, LTE-V, MIMO OTA testing, MPAC, V2X, Antennas, Cables, Design for testability, MIMO systems, Probes, Channel model, Physical dimensions, Standard channel models, Standardized procedure, Standardized testing, Throughput measurements, Vehicular communications, Vehicle to vehicle communications
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-44395 (URN)10.1109/TVT.2019.2956571 (DOI)2-s2.0-85079800813 (Scopus ID)
Available from: 2020-03-09 Created: 2020-03-09 Last updated: 2023-05-25Bibliographically approved
Toss, H. & Karlsson, K. (2019). Radar reflectivity spatial profile of 3D surrogate targets and real vehicles. In: 13th European Conference on Antennas and Propagation, EuCAP 2019: . Paper presented at 13th European Conference on Antennas and Propagation, EuCAP 2019, 31 March 2019 through 5 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Radar reflectivity spatial profile of 3D surrogate targets and real vehicles
2019 (English)In: 13th European Conference on Antennas and Propagation, EuCAP 2019, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

In this paper a method to find a radar reflectivity spatial profile for comparing 3D surrogate targets with real vehicles is proposed. Utilizing this method, the spatial profile can be acquired using only high-level data from an automotive grade radar. For data within a small angular window at arbitrary aspect angle relative to the target, the proposed method back-projects Radar Cross Section (RCS) detections, to build up a spatial profile. This profile can then be used to evaluate multiple scattering centers on targets, which are important during test of autonomous vehicles and active safety functions. The method is used on measured data from 3D surrogate targets as well as real vehicles, which are presented in the paper.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
measurement., radar, RCS, Autonomous vehicles, Fermi level, Measurement, Radar measurement, Reflection, Active safety, Aspect angles, Automotive-grade, Radar reflectivities, Real vehicles, Spatial profiles, Radar cross section
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39670 (URN)2-s2.0-85068467238 (Scopus ID)9788890701887 (ISBN)
Conference
13th European Conference on Antennas and Propagation, EuCAP 2019, 31 March 2019 through 5 April 2019
Available from: 2019-08-07 Created: 2019-08-07 Last updated: 2023-05-25Bibliographically approved
Karlsson, K., Toss, H. & Costagliola, F. (2019). Reducing influence from ground reflection during RCS characterization of automotive targets. In: 13th European Conference on Antennas and Propagation, EuCAP 2019: . Paper presented at 13th European Conference on Antennas and Propagation, EuCAP 2019, 31 March 2019 through 5 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Reducing influence from ground reflection during RCS characterization of automotive targets
2019 (English)In: 13th European Conference on Antennas and Propagation, EuCAP 2019, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

Ground reflection is the major contributor to measurement uncertainty in the characterization of Radar Cross-Section (RCS) of automotive targets. In this paper we present a study of the influence of ground reflection on RCS measurements of large targets - such as real vehicles or surrogate objects - performed on flat outdoor test ranges. The influence of ground reflection and several means to reduce this effect are investigated and compared. Results are derived with theoretical formulas and simple models.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
automotive radar, height diversity, measurement., radar target characterization, Measurement, Radar measurement, Radar reflection, Uncertainty analysis, Ground reflection, Measurement uncertainty, Measurements of, Radar target, Real vehicles, Test range, Theoretical formula, Radar cross section
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39671 (URN)2-s2.0-85068480978 (Scopus ID)9788890701887 (ISBN)
Conference
13th European Conference on Antennas and Propagation, EuCAP 2019, 31 March 2019 through 5 April 2019
Note

Funding details: VINNOVA; Funding text 1: ACKNOWLEDGMENT This work has partly been financed by: The Swedish government agency for innovation systems (VINNOVA) within the HiFi Radar Target project.

Available from: 2019-08-07 Created: 2019-08-07 Last updated: 2023-05-25Bibliographically approved
Nagalapur, K., Strom, E., Brannstrom, F., Carlsson, J. & Karlsson, K. (2018). A Simple Method for Robust Vehicular Communication with Multiple Nonideal Antennas. In: 2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, ICMIM 2018: . Paper presented at 2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, ICMIM 2018, 16 April 2018 through 18 April 2018.
Open this publication in new window or tab >>A Simple Method for Robust Vehicular Communication with Multiple Nonideal Antennas
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2018 (English)In: 2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, ICMIM 2018, 2018Conference paper, Published paper (Refereed)
Abstract [en]

For critical vehicular communication services, such as traffic safety and traffic efficiency, it is advisable to design systems with robustness as the main criteria, possibly at the price of reduced peak performance and efficiency. We describe a simple, low-cost method for combining the output of L nonideal (i.e., nonisotropic) antennas to the input signal to a single-port receiver with the aim to guarantee robustness, i.e., to minimize the probability that K consecutive packets arriving from the worst-case angle-of-arrival are decoded incorrectly. To minimize complexity, the combining network does not estimate or use channel state information (complex channel gains, noise levels, etc.). The combining network consists of L -1 analog phase shifters whose phases are affine functions of time. For a general L and the case when the packet error probability decays exponentially with the received SNR, the optimum slopes of the affine functions can be computed by solving an optimization problem that depends on the antenna far field functions. We provide an analytical solution for the special case of L $=2$ antennas, which turns out to be independent of the antenna patterns. In an experimental setup consisting of two monopole antennas mounted on the roof of a Volvo XC90, the proposed combining method is shown to give significant performance gains compared to using just one of the antennas.

Keywords
Channel state information, Complex networks, Directional patterns (antenna), Efficiency, Monopole antennas, Signal receivers, Analog phase shifter, Angle of arrival, Complex channels, Optimization problems, Packet error probability, Peak performance, Traffic efficiency, Vehicular communications, Signal to noise ratio
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35647 (URN)10.1109/ICMIM.2018.8443547 (DOI)2-s2.0-85053536462 (Scopus ID)9781538617250 (ISBN)
Conference
2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, ICMIM 2018, 16 April 2018 through 18 April 2018
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2023-05-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3135-6603

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