| 1. |
- Basu, Subhadeep, et al.
(författare)
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Antenna Based RF Techniques for Intrabody Communication
- 2020
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Ingår i: 2020 IEEE MTT-S International Microwave Biomedical Conference (IMBioC). - 9781728158679 - 9781728158662
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Konferensbidrag (refereegranskat)abstract
- In this paper, an approach for Intrabody communication(IBC) that uses fat as the communication medium is presented in the ISM band. This study focuses on microwave communication through different biological tissue layers and demonstrates the effect of the thickness of the fat layer on transmission coefficients. Also, the Specific Absorption Rate(SAR) analysis of the antenna has been studied. To validate the simulation results, experimental verification is performed on porcine tissue.
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| 2. |
- Das, Goutam Kumar, et al.
(författare)
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Gain-enhancement technique for wearable patch antenna using grounded metamaterial
- 2020
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:15, s. 2045-2052
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a metamaterial (MTM)-based high-gain compact-wearable antenna for 2.45 GHz industrial, scientific and medical radio band application has been proposed. To achieve the flexibility of the antenna, textile material felt fabric has been chosen as the substrate of the antenna as well as MTM. An omega (omega) like structure has been taken as MTM unit cell design. High value of permeability is utilised for the gain enhancement of the antenna. In addition, very low specific absorption rate (SAR) is obtained using the MTM which makes the proposed antenna suitable for the biomedical application. The proposed antenna has achieved about 3 dB gain enhancement along with SAR value of 0.405 W/kg (1 g tissue). The design has been optimised and the prototype with the optimised parameter has been fabricated and tested over the semi-solid phantom and human body. Further, the proposed antenna over different type of textile material has also been validated.
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| 3. |
- Das, Soumyadeep, et al.
(författare)
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A novel SAR reduction technique for implantable antenna using conformal absorber metasurface
- 2022
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Ingår i: Frontiers in Medical Technology. - : Frontiers Media S.A.. - 2673-3129. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a conformal absorber metasurface has been designed and used for reducing the specific absorption rate (SAR) of an implantable antenna. SAR reduction of implantable antennas is one of the significant design aspects to be considered for their use in modern-day healthcare applications. The introduction of the absorber metasurface restricts the back radiation of the antenna to control the SAR value. This technique decreases the maximum SAR value by 24% and also reduces the average SAR distribution significantly without affecting the desired antenna gain. A reduction in SAR value indicates the decrease in radiation absorption by human tissue, and thus, decreases the possibility of health hazards due to EM radiation. Later, this antenna-absorber system is designed as a capsule module for increased mobility and less-invasiveness. The redundancy of invasive surgery increases acceptance of the capsule module designs of implantable antennas and devices for various biomedical usages. In vitro testing of the fabricated prototype has been carried out inside a multi-layer porcine slab to verify the effectiveness of this unique SAR reduction technique.
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| 4. |
- Das, Soumyadeep, et al.
(författare)
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Implantable antenna gain enhancement using liquid metal-based reflector
- 2020
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Ingår i: Applied Physics A. - : SPRINGER HEIDELBERG. - 0947-8396 .- 1432-0630. ; 126:9
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Tidskriftsartikel (refereegranskat)abstract
- This article presents gain enhancement methodology for a dual-ring slot antenna using a frequency selective surface (FSS) as reflector. The FSS structure is formed with liquid metal placed inside the microfluidic channels created on the surface of the polydimethylsiloxane. Non-toxic liquid metal galinstain has been used to ensure biocompatibility. The FSS structure is placed below the ring slot antenna to reflect the back radiation, which in turn enhances the antenna directivity. Subsequently, the antenna gain has been increased as well. A fabricated prototype of the antenna-FSS system, operating at 2.45 GHz, has been analysed both inside human tissue mimicking fluid and pork slab to validate the simulation results. The inclusion of the liquid metal-based reflector increases antenna gain by almost 4 dB as well as ensures required biocompatibility and flexibility. Also the specific absorption rate of the antenna is observed to be reduced.
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| 5. |
- 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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| 6. |
- Engstrand, Johan, et al.
(författare)
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End-to-End Transmission of Physiological Data from Implanted Devices to a Cloud-Enabled Aggregator Using Fat Intra-Body Communication in a Live Porcine Model
- 2022
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Ingår i: 2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - : Institute of Electrical and Electronics Engineers (IEEE). - 9788831299046 - 9781665416047
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Konferensbidrag (refereegranskat)abstract
- This article presents, for the first time, the end-to-end transmission of physiological data from implanted antennas mimicking sensors to a cloud-enabled aggregator device using fat intra-body communication (fat-IBC). The experiment was performed on a live porcine model in full accordance with ethical standards. Measurement data from two different sensors were collected and sent through a fat-IBC network. The fat-IBC network consisted of three nodes, of which two used antennas implanted in the fat tissue of a live porcine model and one used an on-body antenna placed on the skin. The sensor data was forwarded via Bluetooth Low Energy to an Intel Health Application Platform device, which in turn forwarded the encrypted data to a web server. The experimental results demonstrate that the fat channel can be used in an end-to-end communication scheme, which could involve relaying of sensor data from an implanted device to an external web server.
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| 7. |
- Gaffoglio, Rossella, et al.
(författare)
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Compact Optimized Antenna Solution for Radiation Coupling Improvement in the Subcutaneous Fat Layer
- 2023
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Ingår i: 2023 17th European Conference on Antennas and Propagation, EuCAP. - : IEEE. - 9788831299077 - 9781665475419
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Konferensbidrag (refereegranskat)abstract
- Fat intra-body communication (Fat-IBC) aims at confining microwave propagation to the subcutaneous adipose tissue layer for the creation of a safe high-speed, high-bandwidth data transmission link through the body. This technique can be exploited to connect implantable medical devices and to implement a two-way transmission of recorded neural data and sensory stimulation signals between brain and robotic limbs. In this paper, a compact printed antenna solution for non-invasive tests of the Fat-IBC on non-human primates (NHPs) is proposed. This antenna is a printed monopole with a triangular radiating element embedded into a rigid brick, properly optimized to favor the radiation coupling in a 5mm-thick fat layer and minimize the signal propagation through the air. A promising wave coupling in the adipose tissue is achieved and a compact realizable layout is finalized for future prototyping and testing.
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| 8. |
- Giannetta, H. M. R., et al.
(författare)
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Study of the electrical parameters drift due to mechanical stress in coupled conductors path on flexible polymeric substrate
- 2022
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Ingår i: 2022 Argentine Conference on Electronics (CAE). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728173351 - 9781728192659 ; , s. 37-40
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Konferensbidrag (refereegranskat)abstract
- In this work, the behavior of the drift in electrical impedance values of a coupled device constituting a flat rectangular inductor surrounded by a coupled antenna while subjected to mechanical stresses of over 10,000 bending-stretching cycles has been studied. It has shown correlation with mechanical aging and also is influenced by temperature variations on the device surface. The impact of the mechanical stress was studied separately for the bending-stretching and relaxation phases, considering in both cases the effect of temperature changes and mechanical stress, in order to obtain an adjustment equation for the measured experimental data.. From the fit, it was observed that when using an exponential function for the drift effect due to mechanical stress, the experimental curve was fitted with R-2=0.91 for the bending-stretching phase and R-2=0.79 for the relaxation phase.
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| 9. |
- Krentz, Konrad-Felix, et al.
(författare)
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Dataset: Enabling Offline Tuning of Fat Channel Communication
- 2021
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Ingår i: Proceedings of the 19th ACM Conference on Embedded Networked Sensor Systems (SenSys '21). - New York, NY, USA : ACM.
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Konferensbidrag (refereegranskat)abstract
- Though fat channel communication has advantages over earlier intra-body communication (IBC) technologies based on galvanic or capacitive coupling, the development of a protocol stack on top of fat channel communication is still at its infancy. In this paper, we consider Krentz’s denial-of-sleep-resilient multi-channel medium access control (MAC) layer for IEEE 802.15.4 networks as a starting point for such a protocol stack. In brief, we conducted the following experiment with a phantom that mimics human tissues. Two devices exchanged IEEE 802.15.4 radio frames in a ping-pong manner on the phantom’s fat tissue using Krentz’s MAC layer. The data collected from this experiment lends itself to two purposes. First, it can serve to benchmark and tune algorithms for selecting radio channels. Second, it can also serve to benchmark and tune schemes for deriving cryptographic keys from received signal strength indicator (RSSI) readings. We made the data available at https://uppsala.box.com/s/z2a6jpigswpoifd5l73yophokcfwd88b.
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| 10. |
- Mandal, Bappaditya, et al.
(författare)
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A Low Profile Button Antenna with Back Radiation Reduced By FSS
- 2020
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Ingår i: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Konferensbidrag (refereegranskat)abstract
- In this article, a button antenna with a reflective frequency selective surface(FSS) is proposed to reduce its back radiation. The proposed antenna is low in profile, circularly polarized and designed for Wi-Fi and WLAN applications. The radiating element is made of copper sheet, while a transparent acrylic fibre sheet is used as a substrate. The antenna is fed by a coaxial line, and the FSS layer is designed on jeans material. The patch type FSS with split ring shape has also been designed to operate in the Wi-Fi and WLAN frequency hand (5.250-5.850 GHz) with the centre frequency of 5.51 GHz. The FSS reduces hack radiation of the antenna by 4 dB. The antenna with FSS is fabricated, and a measured gain of 2.9dBi is obtained that matches well with the theoretical value. The antenna is miniaturized by around 61.15% by the slits. To achieve circular polarization characteristic Defected Ground Structure (DGS) slots etched at the ground plane of the triangular patch. The measured impedance bandwidth is 190MHz, and the 3dB axial-ratio (AR) bandwidth is 160MHz, respectively.
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| 11. |
- Mandal, Bappaditya, et al.
(författare)
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Low Profile Implantable Antenna for Fat Intra-Body Communication
- 2020
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Ingår i: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Konferensbidrag (refereegranskat)abstract
- A flexible low profile biocompatible implantable antenna for fat intra-body communication is presented. This article gives an idea of fat channel communication at different distances. The antenna is designed on 0.25 mm thick low loss taconic material. The antenna is covered by 0.1 mm thick PDMS (Polydimethylsiloxane) to ensure biocompatibility with human tissue. A coplanar wave (CPW) microstrip line is used to feed the antenna. This antenna has been optimized to operate at the 2.4 GHz hand frequency in the human three -layer tissue model The simulation, as well as measurement, were done at a minimum distance of 10 mm, and the maximum distance of 70mm between of two implantable antennas. The measured path loss of the fat channel by using the proposed implantable antenna is estimated to be almost 2.5 dB per centimetre. The measured bandwidth of the proposed antenna found to be 660 MHz.
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| 12. |
- Mattsson, Viktor, et al.
(författare)
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MAS : Standalone Microwave Resonator to Assess Muscle Quality
- 2021
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 21:16
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Tidskriftsartikel (refereegranskat)abstract
- Microwave-based sensing for tissue analysis is recently gaining interest due to advantages such as non-ionizing radiation and non-invasiveness. We have developed a set of transmission sensors for microwave-based real-time sensing to quantify muscle mass and quality. In connection, we verified the sensors by 3D simulations, tested them in a laboratory on a homogeneous three-layer tissue model, and collected pilot clinical data in 20 patients and 25 healthy volunteers. This report focuses on initial sensor designs for the Muscle Analyzer System (MAS), their simulation, laboratory trials and clinical trials followed by developing three new sensors and their performance comparison. In the clinical studies, correlation studies were done to compare MAS performance with other clinical standards, specifically the skeletal muscle index, for muscle mass quantification. The results showed limited signal penetration depth for the Split Ring Resonator (SRR) sensor. New sensors were designed incorporating Substrate Integrated Waveguides (SIW) and a bandstop filter to overcome this problem. The sensors were validated through 3D simulations in which they showed increased penetration depth through tissue when compared to the SRR. The second-generation sensors offer higher penetration depth which will improve clinical data collection and validation. The bandstop filter is fabricated and studied in a group of volunteers, showing more reliable data that warrants further continuation of this development.
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| 13. |
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| 14. |
- Mattsson, Viktor, et al.
(författare)
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Muscle Analyzer System : Exploring Correlation Between Novel Microwave Resonator and Ultrasound-based Tissue Information in the Thigh
- 2022
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Ingår i: 2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - : Institute of Electrical and Electronics Engineers (IEEE). - 9788831299046
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Konferensbidrag (refereegranskat)abstract
- A microwave sensor to safely measure quality of muscle tissue for diagnosis and screening of diseases and medical conditions characterized by fat infiltration in muscle is presented. Fat infiltration in muscle may be seen by a lower dielectric constant of muscle at microwave frequencies corresponding to the large contrast between fat and muscle tissues. A planar resonator based on a bandstop filter and optimized to noninvasively interrogate muscle in the thigh on tissue quality is proposed. Currently, a study based on clinical trials is carried out, and, here, we present a preliminary correlation between skin and fat thicknesses and rectus femoris cross sectional area (CSA) measured with ultrasound and the proposed sensor's resonance frequency. CST simulations based on the ultrasound information guide the analysis. We see that although there are signs of a potential correlation between CSA and resonance, skin and fat variability is still an issue to overcome.
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| 15. |
- Mitra, Shamba, et al.
(författare)
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Hip Implant Micromotion monitoring using microwave-photonic hybrid device
- 2023
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Ingår i: 2023 17th European Conference on Antennas and Propagation, EuCAP. - : IEEE. - 9788831299077 - 9781665475419
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Konferensbidrag (refereegranskat)abstract
- In this work, our objective is to develop a noninvasive, portable, user-friendly, non-ionizing, cost-effective system that will be used for post-surgical continuous monitoring of hip implant micromotion. The system we have tried to construct here has been built by integrating microwave sensors and optical interferometric systems. A simple antenna and optoelectrical modulator have been used to devise this hybrid system. Proof of the concept of this novel idea has also been established.
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| 16. |
- Perez, Mauricio D., et al.
(författare)
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Phantom-based evaluation of a planar microwave sensor for non-invasive intracranial pressure monitoring
- 2023
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Ingår i: 2023 IEEE MTT-S International Microwave Biomedical Conference, IMBioC. - : IEEE. - 9781665492171 - 9781665492188 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Intracranial pressure (ICP) measurements are essential to improve current clinical decision schemes in different scenarios: hospital, home, sports field, military field, etc. ICP is fundamental for understanding cerebrospinal fluid (CSF) mechanics and modelling better physiological conditions. Nowadays, several studies have focused on developing non-invasive ICP monitoring methods (nICP) based on different sensing modalities with advantages and disadvantages. Some works have focused on microwave-based sensing; among them is the application of NASA SansEC spectroscopy technology. This work extends previous results on this technology to nICP. Notably, in a simple phantom-based experiment and with a square spiral planar resonator sensor, pressure values up to 48 mmHg could be achievable. The phantom-based experiment consists of a large column tank gradually filled with a liquid that mimics the cerebrospinal fluid (CSF) based on data from the Italian database IFAC. Microwave-based methods for non-invasive intracranial pressure monitoring could be instrumental as tools that can be easily embedded and worn and give indications of brain health to trigger proper care in the future.
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| 17. |
- Rangaiah, Pramod, et al.
(författare)
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Dielectric Characterization and Statistical Analysis of Ex-Vivo Burnt Human Skin Samples for Microwave Sensor Development
- 2023
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Ingår i: IEEE Access. - : IEEE. - 2169-3536. ; 11, s. 4359-4372
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Tidskriftsartikel (refereegranskat)abstract
- The dielectric properties of skin tissues in relation to different degrees of burn are a necessary prerequisite for designing non-invasive microwave sensing modalities. Due to the difficulties in obtaining human tissue samples, such databases are largely unavailable. To bridge the knowledge gap in this field, we attempt to create a dielectric database of various burn-degree skin samples and their statistical analysis in this work. This research is part of the European "Senseburn " project, which aims to create a non-invasive diagnostic tool that can measure the severity and depth of burns on humans in a clinical setting. In this work, several ex-vivo burnt samples were collected from the Uppsala University Hospital (Akademiska sjukhuset, Sweden). Out of that, eight samples with different degrees of burns in various human body locations were selected for the analysis. The dielectric characterization of the categorized samples was done using an Keysight N1501A dielectric open-end co-axial probe Kit. The dielectric characterization was made from 500 MHz to 10 GHz with 1001 points. The measurement was made systematically, and the clinician feedback forms were gathered and analyzed throughout the process. The measurement data followed the FASTCLUS procedure, which was initially analyzed using density plot, convergence, and cubic clustering criteria. For the statistical analysis, 11 frequency points were considered for eight samples. The results of the fundamental statistical analysis using the FASTCLUS procedure resulted in 88 data sets. Later, data sets were analyzed in sample-wise clusters. Every sample was made with two clusters, i.e., cluster 1, which consisted of healthy sectors, and cluster 2, which consisted of burnt sectors. We made the linear approximations for the sample-wise clusters and found the constant real permittivity difference. Furthermore, we found a pattern in the constant real permittivity differences of every sample that is proportional to the burn degrees. This information is needed in order to identify optimization parameters, i.e., the sensitivity with respect to dielectric difference for various burn degrees. For this purpose, extensive measurement campaigns across the microwave frequency band from 500 MHz - 10 GHz were conducted. Based on the analysis of dielectric data, each skin region of interest (ROI) has its own dielectric properties. Additionally, we developed a proof of concept non-invasive flexible microwave sensor based on the dielectric database collected from burnt ex-vivo human tissue samples. In this way, we could distinguish between phantoms with different dielectric properties in the burned human tissue sample range.
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| 18. |
- 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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| 19. |
- 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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| 20. |
- Rangaiah, Pramod, et al.
(författare)
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Preliminary Analysis of Burn Degree Using Non-invasive Microwave Spiral Resonator Sensor for Clinical Applications
- 2022
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Ingår i: Frontiers in Medical Technology. - : Frontiers Media S.A.. - 2673-3129. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The European "Senseburn" project aims to develop a smart, portable, non-invasive microwave early effective diagnostic tool to assess the depth(d) and degree of burn. The objective of the work is to design and develop a convenient non-invasive microwave sensor for the analysis of the burn degree on burnt human skin. The flexible and biocompatible microwave sensor is developed using a magnetically coupled loop probe with a spiral resonator (SR). The sensor is realized with precise knowledge of the lumped element characteristics (resistor (R), an inductor (L), and a capacitor (C) RLC parameters). The estimated electrical equivalent circuit technique relies on a rigorous method enabling a comprehensive characterization of the sensor (loop probe and SR). The microwave resonator sensor with high quality factor (Q) is simulated using a CST studio suite, AWR microwave office, and fabricated on the RO 3003 substrate with a standard thickness of 0.13 mm. The sensor is prepared based on the change in dielectric property variation in the burnt skin. The sensor can detect a range of permittivity variations (ε r 3-38). The sensor is showing a good response in changing resonance frequency between 1.5 and 1.71 GHz for (ε r 3 to 38). The sensor is encapsulated with PDMS for the biocompatible property. The dimension of the sensor element is length (L) = 39 mm, width (W) = 34 mm, and thickness (T) = 1.4 mm. The software algorithm is prepared to automate the process of burn analysis. The proposed electromagnetic (EM) resonator based sensor provides a non-invasive technique to assess burn degree by monitoring the changes in resonance frequency. Most of the results are based on numerical simulation. We propose the unique circuit set up and the sensor device based on the information generated from the simulation in this article. The clinical validation of the sensor will be in our future work, where we will understand closely the practical functioning of the sensor based on burn degrees. The senseburn system is designed to support doctors to gather vital info of the injuries wirelessly and hence provide efficient treatment for burn victims, thus saving lives.
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| 21. |
- Rangaiah, Pramod, et al.
(författare)
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Realization of a Portable Semi-Shielded Chamber for Evaluation of Fat-Intrabody Communication
- 2023
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Ingår i: IEEE Access. - : IEEE. - 2169-3536. ; 11, s. 72743-72755
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a customized portable semi-shielded chamber for torso phantoms to evaluatefat-intrabody communication (Fat-IBC) is presented. Fat-IBC is a technology where human fat tissue isused for microwave communication with intrabody medical devices. The potential clinical applications arevast including central nervous system (brain and spine) communication, cardiovascular disease monitoringand metabolic disorder control. However, validating this technology needs assurance that the signal leakagethrough undesired paths, particularly surface waves and reflections, does not occur. To solve this issue,an effective technique involving a modified design of a semi-shielded chamber is presented. The cross-section of the torso phantoms is about 25 cm × 35 cm and the height about 20 cm. As specified by ISO3745:2012, the maximum object volume that can be measured in a chamber is 5% of the chamber’s internalnet volume. Therefore, the dimensions of the semi-shielded chamber was set to 100 cm × 60 cm × 60 cm.The semi-shielded chamber was constructed out of a wooden crate, covered on the inside with microwaveabsorbers and with thin aluminum sheets on the outside. The experimental evaluation of the semi-shieldedchamber was validated according to standards such as EN 50147-1:1996, IEC 61000-4-3:2020, and IECCISPR 16-1-4:2019. The torso phantom was positioned at the center of the chamber, with a separation wallto ensure signal transmission solely through the phantoms interior and not its surface or chamber walls. Theseparation wall can be modified either to be conformal to the phantom sample or serve as a solid partitiondividing the chamber into two separate volumes for performance measurement. The separation wall wasfound to have a shielding attenuation of 30 dB to 60 dB for frequencies between 0.7 GHz and 18 GHz,respectively, while the corresponding values for the external walls were found to be 45 dB to 70 dB. Thesemi-shielded chamber realized in this work is useful for Fat-IBC technology, brain-computer interface,brain-machine interface, body area networks (BANs), and related applications.
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| 22. |
- Shaw, Tarakeswar, et al.
(författare)
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Design of Metamaterial Based Efficient Wireless Power Transfer System Utilizing Antenna Topology for Wearable Devices
- 2021
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 21:10
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the design of an efficient wireless power transfer (WPT) system using antenna-based topology for the applications in wearable devices is presented. To implement the wearable WPT system, a simple circular patch antenna is initially designed on a flexible felt substrate by placing over a three-layer human tissue model to utilize as a receiving element. Meanwhile, a high gain circular patch antenna is also designed in the air environment to use as a transmitter for designing the wearable WPT link. The proposed WPT system is built to operate at the industrial, scientific and medical (ISM) band of 2.40-2.48 GHz. In addition, to improve the power transfer efficiency (PTE) of the system, a metamaterial (MTM) slab built with an array combination of 3 x 3 unit cells has been employed. Further, the performance analysis of the MTM integrated system is performed on the different portions of the human body like hand, head and torso model to present the versatile applicability of the system. Moreover, analysis of the specific absorption rate (SAR) has been performed in different wearable scenarios to show the effect on the human body under the standard recommended limits. Regarding the practical application issues, the performance stability analysis of the proposed system due to the misalignment and flexibility of the Rx antenna is executed. Finally, the prototypes are fabricated and experimental validation is performed on several realistic wearable platforms like three-layer pork tissue slab, human hand, head and body. The simulated and measured result confirms that by using the MTM slab, a significant amount of the PTE improvement is obtained from the proposed system.
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| 23. |
- 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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| 24. |
- Shaw, Tarakeswar, et al.
(författare)
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Wireless Power Transfer System Design in Reactive Near-Field for Implantable Devices
- 2020
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Ingår i: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008
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Konferensbidrag (refereegranskat)abstract
- In this paper, a wireless power transfer (WPT) system design for charging the bio-implantable devices in the reactive near-field of the antenna is presented. The proposed system is designed to operate in the industrial, scientific, and medical (ISM) of 2.40-2.48 GHz band. The WPT link is constructed with dual-ring slot antenna implanted in a single layer skin tissue model is used as a receiving (Rx) element and a simple patch antenna considered as transmitting (Tx) element. The patch antenna is designed to operate at the ISM of 2.45 GHz, whereas the dual-ring slot is used to obtain wideband characteristics that cover the entire ISM band. The strong mutual coupling between the Tx and Rx elements in the reactive near-field provide high power transfer efficiency for the proposed WPT system. Also, to reflect the real-life application scenario, the analysis of specific absorption rate (SAR) and misalignment between the Tx and Rx element is performed for the proposed system. Finally, the prototype of the Tx and Rx elements are fabricated and experimentally verified by using skin mimicking gel.
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| 25. |
- Shaw, Tarakeswar, et al.
(författare)
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Wireless Power Transfer System Design Using Zero-Index Metamaterial for Implantable Medical Devices
- 2023
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Ingår i: 2023 17th European Conference on Antennas and Propagation, EuCAP. - : IEEE. - 9788831299077 - 9781665475419
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel metamaterial (MTM) integrated, highly efficient approach to designing a wireless power transfer system (WPT), particularly for implantable devices. The proposed implantable WPT system has been constructed by utilizing the radiating principle of the antenna. To design the system, a simple biocompatible circular slot antenna has been constructed on a flexible substrate to use as an implantable receiving (Rx) element. A simple circular patch antenna is designed in air environment to utilize as a transmitting (Tx) element outside the human body for WPT system. Further, the novel zero-index property of the MTM is utilized to enhance the proposed system's power transfer efficiency (PTE). Finally, the prototypes are fabricated, and measurements are performed in a skin-mimicking gel that is equivalent to the human skin tissue. The measured and simulated result confirms the feasibility of the proposed concept by improving the PTE due to the use of MTM.
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| 26. |
- Singh, Adarsh, et al.
(författare)
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A review of electromagnetic sensing for healthcare applications
- 2023
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Ingår i: AEU - International Journal of Electronics and Communications. - : Elsevier. - 1434-8411 .- 1618-0399. ; 171
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Forskningsöversikt (refereegranskat)abstract
- Recent breakthroughs in the fields of antennas, electromagnetic sensors, propagation, and advanced materials have unveiled new opportunities for body area sensing, disease detection, and continuous monitoring. Traditional healthcare approaches not only incur substantial costs but also suffer from inherent drawbacks such as ionizing radiation risks. A range of medical devices, including pacemakers, implants, endoscopy equipment, microwave imaging, and thermal ablation clinical apparatus have greatly benefited from the incorporation of electromagnetic sensors and wireless body area networks. Electromagnetic sensors hold significant potential to transform not only the healthcare sector but also the sports and wearable electronics industries, offering myriad innovative applications. This comprehensive review paper provides an in-depth exploration of the challenges and prospects associated with electromagnetic sensors, including but not limited to microwave probes, resonators, and antennas. We aim to shed light on the potential of these emerging technologies and provide a roadmap for their future development in the context of healthcare and beyond.
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| 27. |
- Singh, Adarsh, et al.
(författare)
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Microwave Antenna-Assisted Machine Learning : A Paradigm Shift in Non-Invasive Brain Hemorrhage Detection
- 2024
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 12, s. 37179-37191
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Tidskriftsartikel (refereegranskat)abstract
- Brain hemorrhages have become increasingly common and can be fatal if left untreated. Current methods for monitoring the progression of the disorder that rely on MRI and PET scans are inconvenient and costly for patients. This has spurred research toward portable and cost-effective techniques for predicting the current stage and malignancy of the hemorrhages. In this study, simulated S-parameter data obtained from a two-antenna system placed over the head is used in conjunction with machine learning to detect the dielectric changes in the brain caused by hemorrhage non-invasively. Several machine learning classifiers are used to analyze the data, and their performance metrics are compared to determine the optimal classifier for this case. The study revealed that Decision Tree, KNN, and Random Forest classifiers are better than SVM and MLP classifiers in terms of accuracy, precision, and recall in predicting Brain hemorrhage at the most probable locations. Contrary to conventional microwave imaging systems requiring several antennas for brain hemorrhage detection, this study demonstrates that integrating machine learning with microwave sensors enables accurate solutions with a reduced antenna count. The results present a transformative strategy for monitoring systems in clinics, where a simple, safe, and low-cost microwave antenna-based system can be intelligently integrated with machine learning to diagnose the presence of Brain hemorrhage.
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| 28. |
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| 29. |
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