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482 results on '"Ukkonen, Leena"'

4. Rock Type Effects on Radio Signal Attenuation

Author

Kordelin, Kai, primary, Virkki, Johanna, additional, Kordelin, Jaana, additional, Norokallio, Juhani, additional, Heikkinen, Jari, additional, Liimatainen, Jyrki, additional, Ukkonen, Leena, additional, and Sydänheimo, Lauri, additional

Published
2023
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15. Next-Generation Healthcare: Enabling Technologies for Emerging Bioelectromagnetics Applications

Author

Kiourti, Asimina, primary, Abbosh, Amin M., additional, Athanasiou, Maria, additional, Bjorninen, Toni, additional, Eid, Aline, additional, Furse, Cynthia, additional, Ito, Koichi, additional, Lazzi, Gianluca, additional, Manoufali, Mohamed, additional, Pastorino, Matteo, additional, Tentzeris, Manos M., additional, Tisdale, Katrina, additional, Topsakal, Erdem, additional, Ukkonen, Leena, additional, Whittow, William G., additional, Zhang, Huanan, additional, and Nikita, Konstantina S., additional

Published
2022
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22. Testing the effects of fabrication parameters on post-fabrication shape change of a 3D printed textile platform

Author

Khan, Zahangir, He, Han, Chen, Xiaochen, Sydänheimo, Lauri, Ukkonen, Leena, Virkki, Johanna, Tampere University, and BioMediTech

Subjects
318 Medical biotechnology, 216 Materials engineering, 217 Medical engineering
Abstract

In this study, a moisture-stimulated 3D printing filament was printed onto an elastic band. The created textile platform changes its shape permanently after exposure to a high-moisture environment. Three main manufacturing parameters – i.e., the printed pattern’s infill percentage, the printed pattern’s thickness, and the textile stretch – were tested to study their effects on the platform curving process. It was observed that an increase of the printed pattern’s infill density from 20 % to 80 %, or the printed pattern’s thickness from 1.3 mm to 1.7 mm, resulted in reduced curvature, whereas an increase in the elastic band’s stretch extent from 120 % to 130 % of its original length increased the curvature. The achieved results can be very useful in optimizing and programming moisture sensor performance, as several sensor manufacturing parameters can be modified according to the application and use environment. publishedVersion

Published
2021

34. Textile-based Passive Sensor for Air Humidity

Author

He, Han, primary, Chen, Xiaochen, additional, Khan, Zahangir, additional, Sydanheimo, Lauri, additional, Ukkonen, Leena, additional, Li, Jiahui, additional, Nishikawa, Hiroshi, additional, and Virkki, Johanna, additional

Published
2020
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36. Equivalent Circuit Approximation to the Connector-Line Transition at High Frequencies using Two Microstrip Lines and Data Fitting.

Author

Le, Duc, Pournoori, Nikta, Sydänheimo, Lauri, Ukkonen, Leena, and Björninen, Toni

Subjects
MICROSTRIP transmission lines, LUMPED elements, PERMITTIVITY, ELECTRIC circuits, CIRCUIT elements
Abstract

This article presents a method of obtaining an equivalent lumped element circuit to model the electrical connector-line transitions in the ultra-high frequency (UHF) band. First, the scattering matrices of two microstrip transmission lines that are otherwise identical but have the physical lengths of d and 2d are measured. Next, the theoretical model of the lines cascaded with the connector-line transitions modeled as lumped element circuits is established. The selection of the line lengths to be d and 2d results in an over determined system of equations that links the circuit component values to the two-port network parameters of the cascaded system. Finally, the least-squares data fitting procedure yields the best-fit component values. The results show that in our tested scenario, 3-component reactive circuit models well the transitions. Compared with the previous methods, the proposed approach does not require knowledge of the dielectric properties of the substrate of the measured transmission lines. This property integrates the method with our previous work on estimating a microstrip line substrate's relative permittivity and loss tangent. The obtained transition circuit model is also validated through the testing of two quarter-wave transformers. The lines and transformers are implemented on a textile substrate to highlight the method's applicability to wearable textile-based electronics. [ABSTRACT FROM AUTHOR]

Published
2021
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