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Choudhary, V., Rönnow, D. & Tripathy, M. R. (2023). A printed lens in antenna’s aperture to improve the performance of UWB-radar system. International Journal of Systems Assurance Engineering and Management, 14, 603-609
Open this publication in new window or tab >>A printed lens in antenna’s aperture to improve the performance of UWB-radar system
2023 (English)In: International Journal of Systems Assurance Engineering and Management, ISSN 0975-6809, E-ISSN 0976-4348, Vol. 14, p. 603-609Article in journal (Refereed) Published
Abstract [en]

We present a printed lens for radar applications. The structure of the presented lens consists of an array of modified micro-strip lines, which is positioned in the antenna’s aperture on the same planar substrate. Simulations show that the gain and directivity increase with the proposed lens in a wide band frequency band. The proposed design is insensitive to rotation of the antenna. This paper focuses on real industrial applications and problems. Further, we show that the lens can be used to improve the object detection ability of an ultrawide band radar system, which is used in industrial applications such as non-destructive monitoring of built-structures and for use in the renovation process. The signal to noise ratio is improved. Furthermore, we show how the microwave lens can also be used to reduce the clutter in applications where the complex refractive index of objects is determined. Further, different simulated results (for different cases) are compared, presented and concluded.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Microwave printed lens, UWB radar, Lens, Antipodal-Vivaldi antenna, Radar applications
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37017 (URN)10.1007/s13198-021-01341-2 (DOI)000692964500002 ()2-s2.0-85114378124 (Scopus ID)
Available from: 2021-09-13 Created: 2021-09-13 Last updated: 2023-07-06Bibliographically approved
Bautista Gonzalez, O. & Rönnow, D. (2023). A Study of OBF-ARMAX Performance for Modelling of a Mechanical System Excited by a Low Frequency Signal for Condition Monitoring. In: Janusz Kacprzyk (Ed.), Recent Developments in Model-Based and Data-Driven Methods for Advanced Control and Diagnosis: (pp. 73-82). Springer
Open this publication in new window or tab >>A Study of OBF-ARMAX Performance for Modelling of a Mechanical System Excited by a Low Frequency Signal for Condition Monitoring
2023 (English)In: Recent Developments in Model-Based and Data-Driven Methods for Advanced Control and Diagnosis / [ed] Janusz Kacprzyk, Springer , 2023, p. 73-82Chapter in book (Refereed)
Abstract [en]

A digital twin of a mechanical system (a pair of axial rolls in a ring mill used in a steel plant) with poles close to the unit circle and the real axis in the discrete pole-zero map was built. The system was excited by a signal concentrated in the low-frequency band. For this particular case, it is shown that the ad-hoc combination of ARMAX and orthonormal basis filter model structures outperform model structures based on either ARMAX or orthonormal basis functions when estimating the poles of the basis by analyzing the data in the frequency domain. The followed modelling methodology of the system is described in detail to help replicate the work for similar systems in the steel industry. Real production data from a steel plant were used in contrast to previous studies, where the combination of ARX and ARMAX with orthonormal basis filter model structures was evaluated using simulated data instead of real data. We believe that the resultant model can be used when having systems with poles close to the unit circle and real axis and poor excited input signal concentrated in the low frequency band. The resultant model can be used for condition monitoring and failure detection.

Place, publisher, year, edition, pages
Springer, 2023
Series
Studies in Systems, Decision and Control (SSDC), ISSN 2198-4182, E-ISSN 2198-4190 ; 467
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-42666 (URN)10.1007/978-3-031-27540-1_7 (DOI)2-s2.0-85162239790 (Scopus ID)978-3-031-27540-1 (ISBN)978-3-031-27539-5 (ISBN)
Available from: 2023-07-03 Created: 2023-07-03 Last updated: 2023-07-03Bibliographically approved
Ottosson, P., Andersson, D., Choudhary, V. & Rönnow, D. (2023). An ultra-wideband system for measuring the dielectric properties of mineral compounds in a heat-reaction chamber at high temperatures. IEEE Transactions on Instrumentation and Measurement, 72, Article ID 6003810.
Open this publication in new window or tab >>An ultra-wideband system for measuring the dielectric properties of mineral compounds in a heat-reaction chamber at high temperatures
2023 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 72, article id 6003810Article in journal (Refereed) Published
Abstract [en]

A measurement system for the measurement of microwave dielectric properties of mineral compounds at temperatures up to +1000°C is presented. It includes the simultaneous measurement of mass and temperature. Samples volumes in the range 0.01 to 0.1 m 3 can be studied. The system comprises a heat reaction chamber on a mass scale with mounted ultra-wideband (UWB) radio sensors and temperature probes. The complex refractive index is determined from the UWB signals using a technique with windowing to suppress interference and fitting of a modelled signal to the experimental ones. The developed method is validated by measuring the complex refractive index of water from +82°C down to +23°C and comparing with literature values. The systems is used to study calcination of limestone, i.e. the chemical decomposition of CaCO 3 to CaO and CO 2 when heated up to +1000°C. The chemical decomposition is clearly seen as a decrease in mass and as significant changes in the complex refractive index. The system could be used also for other mineral compounds and other types of materials.

Place, publisher, year, edition, pages
IEEE, 2023
Keywords
calcination; dielectric permittivity; heat-chamber; High-temperature techniques; radio measurement; thermogravimetry; ultra-wideband; UWB
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-41588 (URN)10.1109/tim.2023.3265760 (DOI)000979582400014 ()2-s2.0-85153388884 (Scopus ID)
Funder
Swedish Energy Agency
Available from: 2023-04-13 Created: 2023-04-13 Last updated: 2023-06-01Bibliographically approved
Bautista Gonzalez, O. & Rönnow, D. (2023). Time series modelling of a radial-axial ring rolling system. International journal of Modeling, identification and control, 43(1), 13-25
Open this publication in new window or tab >>Time series modelling of a radial-axial ring rolling system
2023 (English)In: International journal of Modeling, identification and control, ISSN 1746-6172, E-ISSN 1746-6180, Vol. 43, no 1, p. 13-25Article in journal (Refereed) Published
Abstract [en]

In the present work, a digital twin of a radial-axial ring rolling machine was built by modelling the time series of the positions of the tools and control signals rather than the metrics of the produced rings, as performed in previous studies. Real data from the industry was used for modelling. The used model selection methodology is shown in detail to replicate such work for similar systems in the steel industry. The modelling results of ARX, ARMAX and orthonormal basis model structures are shown; additionally, they were validated considering SISO and MIMO systems. The modelling results were better when the subsystems considered were ARMAX and MISO than when ARX and SISO were taken into consideration. The best modelling results were obtained when physical knowledge was included in the model structure. Lastly, it was found that the model error of the horizontal subsystem could be used for predictive maintenance.

Place, publisher, year, edition, pages
Inderscience, 2023
Keywords
radial-axial ring rolling, steel industry, grey-box modelling, MIMO systems, system identification, time series
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-42825 (URN)10.1504/ijmic.2023.132108 (DOI)001027905200002 ()2-s2.0-85166395255 (Scopus ID)
Available from: 2023-08-11 Created: 2023-08-11 Last updated: 2023-11-23Bibliographically approved
Choudhary, V., Ottosson, P., Andersson, D. & Ronnow, D. (2022). A Non-destructive Testing Method in Industrial Processes to Determine the Complex Refractive Index Using Ultra-Wide Band Radio. IEEE Sensors Journal, 22(8), 7752-7762
Open this publication in new window or tab >>A Non-destructive Testing Method in Industrial Processes to Determine the Complex Refractive Index Using Ultra-Wide Band Radio
2022 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 22, no 8, p. 7752-7762Article in journal (Refereed) Published
Abstract [en]

An ultra-wide band measurement method for determining the complex refractive index of large-volume objects is presented. The method is intended for industrial non-destructive testing. It uses a frequency-domain technique in which transmitted radio pulses are analyzed and the effects of near field and coupling on the determined refractive index are compensated. Measurements were performed in an industrial setup with electromagnetic sensors buried in the object. The results are presented for woodchips as an object. The refractive index was experimentally determined in the frequency range 0.5-3.0 GHz. Additionally, we designed and manufactured planar quasi-differential elliptical-antennas as electromagnetic sensors. The results from the industrial measurement setup were compared with the results of the laboratory setup, in which the sensors were placed outside the test box and near field and coupling effects could be neglected. The complex refractive index determined for the two setups was in good agreement, which corroborates the proposed method for compensating for coupling and near-field effects. The complex refractive index of woodchips changes with the moisture content. It is experimental verified using the industrial setup that the moisture content can be determined with a 2 percent error.

Place, publisher, year, edition, pages
IEEE, 2022
Keywords
complex refractive index, non-destructive testing, UWB radar sensor, moisture, wood-based material, radio-link system, EM sensor, woodchips, near field coupling, radio measurement
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-38047 (URN)10.1109/jsen.2022.3155874 (DOI)000803129500036 ()2-s2.0-85125711660 (Scopus ID)
Funder
Swedish Energy Agency
Available from: 2022-03-07 Created: 2022-03-07 Last updated: 2023-05-23Bibliographically approved
Rönnow, D., Ottosson, P. & Andersson, D. (2022). Microwave complex permittivity and anisotropy of conifer wood chips vs moisture content: experiments and modeling. Journal of Wood Science, 68(1), Article ID 22.
Open this publication in new window or tab >>Microwave complex permittivity and anisotropy of conifer wood chips vs moisture content: experiments and modeling
2022 (English)In: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 68, no 1, article id 22Article in journal (Refereed) Published
Abstract [en]

The complex microwave permittivity-including anisotropy- of wood chips of softwood has been measured for different moisture contents in the band 0.75 to 2.5 GHz using an ultra-wide band radio transmission technique. The real and imaginary parts increase monotonically with moisture content. The wood chips are oriented by gravity, which gives anisotropic permittivity. The anisotropy ratio of the real part increases from 1.1 to 1.6 with moisture content from 0 to 120%. The anisotropy ratio of the imaginary part is around 2.5 at all moisture contents. Effective medium models were used to model the permittivity. The Bruggeman, and two versions of the Maxwell Garnett model gave good results at low moisture content (below the fiber saturation point). Above the fiber saturation point only the Bruggeman model gave results in agreement with experiments. The difference in model performance suggests that the free water does not follow the wood chips geometry.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Permittivity, Moisture content, Anisotropy, Effective medium modeling, Wood chips, Soft wood, Ultra wideband radar
National Category
Wood Science
Identifiers
urn:nbn:se:hig:diva-38472 (URN)10.1186/s10086-022-02026-5 (DOI)000782603200001 ()2-s2.0-85128299711 (Scopus ID)
Funder
Swedish Energy Agency
Available from: 2022-04-28 Created: 2022-04-28 Last updated: 2022-12-05Bibliographically approved
Panigrahi, S. R. & Rönnow, D. (2021). Evaluating nonlinear distortion of single and dual channel excitation of an amplifier at 24 GHz. Microwave and optical technology letters (Print), 63(9), 2315-2319
Open this publication in new window or tab >>Evaluating nonlinear distortion of single and dual channel excitation of an amplifier at 24 GHz
2021 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 63, no 9, p. 2315-2319Article in journal (Refereed) Published
Abstract [en]

Experimental characterization of an amplifier's nonlinear properties at 24 GHz is presented in single and dual-band operation using orthogonal frequency-division multiplex signals. A test system for characterizing an amplifier's nonlinear properties at millimeter-wave frequencies for single and dual-band excitation is presented. The use of standard instrument enables a feasible test system. Analytical expressions based on a statistical analysis of signals and hardware impairments were used to analyze the experimental data versus power level and found to describe well the experimental results, including inter- and cross-modulation distortion. Parameters are derived that could be used in system studies.

Place, publisher, year, edition, pages
Wiley, 2021
Keywords
24 GHz ISM band, 5G, amplifier, dual band, millimeter wave, nonlinear distortion
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-35909 (URN)10.1002/mop.32889 (DOI)000652823900001 ()2-s2.0-85106280066 (Scopus ID)
Available from: 2021-06-03 Created: 2021-06-03 Last updated: 2021-07-01Bibliographically approved
Choudhary, V. & Rönnow, D. (2020). A Nondestructive Testing Method for the Determination of the Complex Refractive Index Using Ultra Wideband Radar in Industrial Applications. Sensors, 20(11), Article ID 3161.
Open this publication in new window or tab >>A Nondestructive Testing Method for the Determination of the Complex Refractive Index Using Ultra Wideband Radar in Industrial Applications
2020 (English)In: Sensors, E-ISSN 1424-8220, Vol. 20, no 11, article id 3161Article in journal (Refereed) Published
Abstract [en]

An ultra-wide band radar reflection measurement technique for industrial applications is introduced. A new method for determining the complex refractive index (or equivalently the relative permittivity) of objects with planar interfaces is presented. The object thickness can also be obtained experimentally. The method is a combination of time and frequency domain techniques. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. The method is relatively insensitive to hardware impairments such as frequency dependence of antennas and analog front end. The method is designed for industrial in-line measurements on objects on conveyor belts. Results are presented for solid wood and wood chips; the complex refractive index is determined in the frequency range 0.5 to 2.0 GHz for the moisture content of 3.6–10% for solid wood and 30–50% for wood chips. Polarimetric measurements are used; wood and wood chips are anisotropic.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
ultra wideband radar, UWB, dielectric properties, refractive index, polarimetry, wood based materials, moisture, nondestructive testing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-32521 (URN)10.3390/s20113161 (DOI)000552737900154 ()32498460 (PubMedID)2-s2.0-85085939119 (Scopus ID)
Available from: 2020-06-10 Created: 2020-06-10 Last updated: 2023-05-23Bibliographically approved
Ivanchenko, I., Khruslov, M., Popenko, N., Plakhtii, V., Rönnow, D. & Shestopalov, Y. (2020). A novel resonance method for determining the complex permittivity of local inclusions in a rectangular waveguide. Measurement science and technology, 31(9), Article ID 097001.
Open this publication in new window or tab >>A novel resonance method for determining the complex permittivity of local inclusions in a rectangular waveguide
Show others...
2020 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 31, no 9, article id 097001Article in journal (Refereed) Published
Abstract [en]

A novel resonance method for determining the complex permittivity of materials in the X-band is proposed. A distinctive feature of this method is that the sample under test, located in a radio-transparent isotropic and homogeneous dielectric matrix, is both a local inclusion and the excitation element of the resonance in the microwave module 'waveguide–dielectric matrix–inclusion'. The complex permittivity of an inclusion is determined by comparing the measured resonance frequency and quality factor with the computed database value. The permittivity and loss factor of microwave ceramics, natural granite and ferrite are investigated, as well as crystals of lead fluoride PbF2 doped with holmium trifluoride HoF3 and erbium fluoride ErF3 of different concentrations. The method allows the permittivity and loss tangent to be determined with uncertainties of 0.1% and 5%, respectively.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2020
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-33150 (URN)10.1088/1361-6501/ab870f (DOI)000544634800001 ()
Available from: 2020-07-02 Created: 2020-07-02 Last updated: 2020-08-17Bibliographically approved
Händel, P., Demir, Ö. T., Björnson, E. & Rönnow, D. (2020). Impact of Backward Crosstalk in 2×2 MIMO Transmitters on NMSE and Spectral Efficiency. IEEE Transactions on Communications, 68(7), 4277-4292
Open this publication in new window or tab >>Impact of Backward Crosstalk in 2×2 MIMO Transmitters on NMSE and Spectral Efficiency
2020 (English)In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 68, no 7, p. 4277-4292Article in journal (Refereed) Published
Abstract [en]

We consider backward crosstalk in 2×2 transmitters, which is caused by crosstalk from the outputs of the transmitter to the inputs or by the combination of output crosstalk and impedance mismatch. We analyze its impact via feedback networks together with third-order power amplifier non-linearities. We utilize the Bussgang decomposition to express the distorted output signals of the transmitter as a linear transformation of the input plus uncorrelated distortion. The normalized mean-square errors (NMSEs) between the distorted and desired amplified signals are expressed analytically and the optimal closed-form power back-off that minimizes the worst NMSE of the two branches is derived. In the second part of the paper, an achievable spectral efficiency (SE) is presented for the communication from this “dirty” transmitter to another single-antenna receiver. The SE-maximizing precoder is optimally found by exploiting the hardware characteristics. Furthermore, the optimal power back-off is analyzed for two sub-optimal precoders, which either do not exploit any hardware knowledge or only partial knowledge. The simulation results show that the performance of these sub-optimal precoders is close-to-optimal. We also discuss how the analysis in this paper can be extended to transmitters with an arbitrary number of antenna branches.

Place, publisher, year, edition, pages
IEEE, 2020
Keywords
Crosstalk, MIMO communication, Distortion, Hardware, Transmitting antennas, Analytical models, Orthogonal frequency-division multiplexing (OFDM), input back-off, power amplifier, transmitter hardware imperfections, spectral efficiency
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Intelligent Industry
Identifiers
urn:nbn:se:hig:diva-32205 (URN)10.1109/TCOMM.2020.2988927 (DOI)000552840100027 ()
Available from: 2020-04-23 Created: 2020-04-23 Last updated: 2020-11-23Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2887-049x

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