| 1. |
- Ebrahimizadeh, Javad, et al.
(författare)
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Time Reversal Microwave Imaging of Realistic Numerical Head Phantom for Bone Flap Healing Follow-up
- 2020
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Ingår i: 2020 IEEE MTT-S International Microwave Biomedical Conference (IMBioC). - 9781728158662 - 9781728158679
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Konferensbidrag (refereegranskat)abstract
- This paper presents the feasibility of using a microwave imaging system for monitoring bone mineralization progress overtime after craniotomy surgery. Any variation in the composition of the bone flap can be monitored as a variation in the intensity of the image. A simulation is conducted on a head structure derived from a numerical head phantom based on anatomically realistic MRI-derived FDTD models using commercial CST 2019 software. For simulation, a defect is provided in the skull layer surrounded by a 9-elements antenna. Applying Space-Frequency Time Reversal (TR) method, the image of defect is constructed for different permittivity of the defect ranging from 16 to 36. Results show that the image intensity at the defect location will decrease as the permittivity of the defect decreases.
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| 2. |
- Rangaiah, Pramod K. B., et al.
(författare)
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Clustering of Dielectric and Colour Profiles of an Ex-vivo Burnt Human Skin Sample
- 2020
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Ingår i: 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Konferensbidrag (refereegranskat)abstract
- This work aims to introduce two techniques to characterize human burnt skin based on permittivity measurement and image processing. The first method is the sectorized measurement of permittivity (dielectric profiling, DEP) by using an open-end coaxial probe technique. The second method is the analysis of color variation in the burnt skin sample through image processing. Statistical analysis is done using tools such as Analysis of Variance (ANOVA), k-means, in order to classify, evaluate the data. As part of the classification, the experimental data are clustered into five groups based on the distribution of means (dielectric profiles) and centroids (color profiles). The color image is converted into a gray image and resized to a one-dimensional array. Furthermore, the analysis is done based on the intensity range, various centroid values, and silhouette analysis. The clustering results we obtained with these two methods can be used for comparing the dielectric characteristics with the color variation of the burnt human skin to assess burn degree.
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| 3. |
- Rangaiah, Pramod K. B., et al.
(författare)
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Design of constant width branch line directional coupler for the microwave sensing application
- 2020
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Ingår i: 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the design of directional branch-line coupler using constant width multiple sections of series and open microstrip line stubs. This device is operating at the center frequency of 2.45 GHz. The designed coupler is having good performance for the frequency band 2-3 GHz. The proposed design is compared with a typical branch line coupler and shows the improved performance. The design is simulated and fabricated on the Fibreglass-resin laminate (FR4) substrate of height 1.5 mm. The results of simulated and experimented circuits are discussed and analyzed. The circuit is measured using Combination Analyzer N9918A Field Fox Handheld Microwave Analyzer. The proposed topology is easy to design and fabricate with a planar microstrip line technology. The designed coupler shows the good results at 2.45GHz i.e. S 11 = -61.26 dB, S 21 = -45 dB, S 31 = -2dB and S 41 = -4.5dB. The main target of this work is to design a coupler to differentiate between transmitted and reflected signals in the split ring resonator (SRR) sensor for Bone Density Measurement Analysis (BDAS) system.
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| 4. |
- Schiele, Carina, 1993-, et al.
(författare)
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Hybrid Foams based on Multi-Walled Carbon Nanotubes and Cellulose Nanocrystals for Anisotropic Electromagnetic Shielding and Heat Transport
- 2024
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Ingår i: Advanced Materials Interfaces. - 2196-7350. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- Lightweight and mechanically robust hybrid foams based on cellulose nanocrystals (CNC) and multi-walled carbon nanotubes (MWCNT) with an anisotropic structure are prepared by directional ice-templating. The anisotropic hybrid CNC-MWCNT foams displayed a combination of highly anisotropic thermal conductivity and an orientation-dependent electromagnetic interference (EMI) shielding with a maximum EMI shielding efficiency (EMI-SE) of 41–48 dB between 8 and 12 GHz for the hybrid foam with 22 wt% MWCNT. The EMI-SE is dominated by absorption (SEA) which is important for microwave absorber applications. Modelling of the low radial thermal conductivity highlighted the importance of phonon scattering at the heterogeneous CNC-MWCNT interfaces while the axial thermal conductivity is dominated by the solid conduction along the aligned rod-like particles. The lightweight CNC-MWCNT foams combination of an anisotropic thermal conductivity and EMI shielding efficiency is unusual and can be useful for directional heat transport and EMI shielding.
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| 5. |
- Schiele, Carina, 1993-, et al.
(författare)
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Hybrid Foams based on Multi-Walled Carbon Nanotubes and Cellulose Nanocrystals for Anisotropic Electromagnetic Shielding and Heat Transport
- 2024
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Ingår i: Advanced Materials Interfaces. - : Wiley-VCH Verlagsgesellschaft. - 2196-7350. ; 11:12
-
Tidskriftsartikel (refereegranskat)abstract
- Lightweight and mechanically robust hybrid foams based on cellulose nanocrystals (CNC) and multi-walled carbon nanotubes (MWCNT) with an anisotropic structure are prepared by directional ice-templating. The anisotropic hybrid CNC-MWCNT foams displayed a combination of highly anisotropic thermal conductivity and an orientation-dependent electromagnetic interference (EMI) shielding with a maximum EMI shielding efficiency (EMI-SE) of 41–48 dB between 8 and 12 GHz for the hybrid foam with 22 wt% MWCNT. The EMI-SE is dominated by absorption (SEA) which is important for microwave absorber applications. Modelling of the low radial thermal conductivity highlighted the importance of phonon scattering at the heterogeneous CNC-MWCNT interfaces while the axial thermal conductivity is dominated by the solid conduction along the aligned rod-like particles. The lightweight CNC-MWCNT foams combination of an anisotropic thermal conductivity and EMI shielding efficiency is unusual and can be useful for directional heat transport and EMI shielding.
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| 6. |
- Shaw, Tarakeswar, et al.
(författare)
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Metamaterial integrated highly efficient wireless power transfer system for implantable medical devices
- 2024
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Ingår i: AEU - International Journal of Electronics and Communications. - : Elsevier. - 1434-8411 .- 1618-0399. ; 173
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Tidskriftsartikel (refereegranskat)abstract
- In this article, a novel and highly efficient metamaterial (MTM) integrated approach is presented for the development of a wireless power transfer system (WPT) specifically tailored for implantable medical devices. The system is designed by using a biocompatible implantable ring slot antenna constructed on a flexible dielectric, functioning as a receiving (Rx) antenna. Additionally, a conventional patch antenna is modelled for the use in free space, serving as an external transmitting (Tx) element. By exploiting the unique characteristics of MTMs, the power transfer efficiency (PTE) of the introduced system is effectively improved. To ensure the system's performance stability in real-time application scenario, the effects of misalignment (lateral and angular) and the flexibility of the implantable antenna are meticulously performed. The prototypes of the Tx, Rx, and MTM structures are fabricated, and comprehensive measurements are performed in human -equivalent tissue models, such as skin-mimicking gel and minced pork. Both the simulated and measured results established the proposed methodology, showcasing marked improvements in PTE due to the use of MTMs. The efficiency of the pioneering MTM-integrated WPT system increases from 0.19% to 3.07% in skin-mimicking gel and from 0.24% to 3.26% in minced pork, respectively. This study highlights the potential of MTM-integrated WPT systems in advancing the field of implantable medical devices and expanding their practical applicability.
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