| 1. |
- Asan, Noor Badariah, et al.
(författare)
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Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies
- 2018
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.
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| 2. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Effect of Thickness Inhomogeneity in Fat Tissue on In-Body Microwave Propagation
- 2018
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Ingår i: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBIOC). - Philadelphia, USA : IEEE. - 9781538659182 ; , s. 136-138
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Konferensbidrag (refereegranskat)abstract
- In recent studies, it has been found that fat tissue can be used as a microwave communication channel. In this article, the effect of thickness inhomogeneities in fat tissues on the performance of in-body microwave communication at 2.45 GHz is investigated using phantom models. We considered two models namely concave and convex geometrical fat distribution to account for the thickness inhomogeneities. The thickness of the fat tissue is varied from 5 mm to 45 mm and the Gap between the transmitter/receiver and the starting and ending of concavity/convexity is varied from 0 mm to 25 mm for a length of 100 mm to study the behavior in the microwave propagation. The phantoms of different geometries, concave and convex, are used in this work to validate the numerical studies. It was noticed that the convex model exhibited higher signal coupling by an amount of 1 dB (simulation) and 2 dB (measurement) compared to the concave model. From the study, it was observed that the signal transmission improves up to 30 mm thick fat and reaches a plateau when the thickness is increased further.
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| 3. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Effects of Blood Vessels on Fat Channel Microwave Communication
- 2018
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Ingår i: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
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Konferensbidrag (refereegranskat)abstract
- This study aims to investigate the reliability of intra-body microwave propagation through the fat tissue in presence of blood vessels. Here, we consider three types of blood vessels with different sizes. We investigate the impact of the number of blood vessels and their alignment on the transmission of microwave signals through the fat channel. In our study, we employ two probes that act as a transmitter and a receiver. The probes are designed to operate at the Industrial, Scientific, and Medical radio band (2.45 GHz). For a channel length of 100 mm, our results indicate that the presence of the blood vessels may increase the channel path loss by similar to 1.5 dB and similar to 4.5 dB when the vessels are aligned and orthogonally aligned with the fat channel, respectively.
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| 4. |
- Asan, Noor Badariah, 1984-, et al.
(författare)
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Impact of Blood Vessels on Data Packet Transmission Through the Fat Channel
- 2018
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Ingår i: 2018 IEEE INTERNATIONAL RF AND MICROWAVE CONFERENCE (RFM 2018). - : IEEE conference proceedings. - 9781538667200 - 9781538667194 - 9781538667217 ; , s. 196-198
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Konferensbidrag (refereegranskat)abstract
- The reliability of intra-body wireless communication systems is very important in medical applications to ensure the data transmission between implanted devices. In this paper, we present newly developed measurements to investigate the effect of blood vessels on the data packet reception through the fat tissue. We use an IEEE 802.15.4-based WBAN prototype to measure the packet reception rate (PRR) through a tissue-equivalent phantom model. The blood vessels are modelled using copper rods. We measure the PRR at the frequency 2.45 GHz for several power levels. The results revealed that the presence of blood vessels aligned with the fat channel has tiny influence on the PRR when measured over the range -25 dBm to 0 dBm power level and for different blood vessels positions. Our investigations show 97% successful PRR through a 10 cm length fat channel in presence of the blood vessels.
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| 5. |
- Mathur, Parul, et al.
(författare)
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An Efficient Method for Computing the Interaction of Open Ended Circular Waveguide with a Layered Media
- 2018
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Ingår i: Progress In Electromagnetics Research Letters. - : E M W PUBLISHING. - 1937-6480. ; 76, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a new method for studying the near-field electromagnetic interaction between a dielectric filled open ended circular waveguide (OECW) and a layered dielectric structure. The proposed model is based on plane wave spectrum theory using a novel and computationally efficient two step integration method. The first integral, involving multiple singularities in the integration path, is efficiently solved using a deformed elliptical integration path which encircles the singularities of the integral. The infinite domain tail integral involving the slowly converging integrand is further solved using an efficient trigonometric transformation. The proposed OECW based method is capable of determining the unknown material properties of any layered dielectric medium, and hence finds application in nondestructive evaluation of materials.
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| 6. |
- Perez, Mauricio D., et al.
(författare)
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New Approach for Clinical Data Analysis of Microwave Sensor Based Bone Healing Monitoring System in Craniosynostosis Treated Pediatric Patients
- 2018
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Ingår i: 2018 IEEE Conference On Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
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Konferensbidrag (refereegranskat)abstract
- In the BDAS project one of the goals is to provide a solution to the monitoring bone healing issue complementing current techniques. Data have been collected in clinical trials from infants treated for Craniosynostosis by a craniotomy surgery. The data are collected with a biomedical sensor based in microwave technology. This sensor could be able to sense changes in the composition of the different tissues in the upper-hemisphere of the head by noticing a difference in the propagation of the microwaves, as the bone injury from the craniotomy heals over time. In this thesis, we analyse the clinical data in BDAS project incorporating new approaches with respect to previous analysis methods. These new approaches could give new insight into the proposed solution, but more analysis need to be done.
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| 7. |
- Redzwan, Syaiful, et al.
(författare)
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Initial in-vitro trial for intra-cranial pressure monitoring using subdermal proximity-coupled split-ring resonator
- 2018
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Ingår i: IMBioc 2018 - 2018 IEEE/MTT-S International Microwave Biomedical Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538659182 ; , s. 73-75
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Konferensbidrag (refereegranskat)abstract
- Intra cranial pressure (ICP) monitoring is used in treating severe traumatic brain injury (TBI) patients. All current clinical available measurement methods are invasive presenting considerable social costs. This paper presents a preliminary investigation of the feasibility of ICP monitoring using an innovative microwave-based non-invasive approach. A phantom mimicking the dielectric characteristics of human tissues of the upper part of the head at low microwave frequencies is employed together to a proof-of-concept prototype based on the proposed approach consisting in a readout system and a sub-dermally implanted passive device, both based in split ring resonator techniques. This study shows the potential of our approach to detect two opposite pressure variation stages inside the skull. The employed phantom model needs to be improved to support finer variations in the pressure and better phantom parts, principally for the skull mimic and the loss tangent of all mimics.
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| 8. |
- Redzwan, Syaiful, et al.
(författare)
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Split-Ring Resonator Sensor Penetration Depth Assessment Using In Vivo Microwave Reflectivity and Ultrasound Measurements for Lower Extremity Trauma Rehabilitation
- 2018
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 18:2
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Tidskriftsartikel (refereegranskat)abstract
- In recent research, microwave sensors have been used to follow up the recovery of lower extremity trauma patients. This is done mainly by monitoring the changes of dielectric properties of lower limb tissues such as skin, fat, muscle, and bone. As part of the characterization of the microwave sensor, it is crucial to assess the signal penetration in in vivo tissues. This work presents a new approach for investigating the penetration depth of planar microwave sensors based on the Split-Ring Resonator in the in vivo context of the femoral area. This approach is based on the optimization of a 3D simulation model using the platform of CST Microwave Studio and consisting of a sensor of the considered type and a multilayered material representing the femoral area. The geometry of the layered material is built based on information from ultrasound images and includes mainly the thicknesses of skin, fat, and muscle tissues. The optimization target is the measured S-11 parameters at the sensor connector and the fitting parameters are the permittivity of each layer of the material. Four positions in the femoral area (two at distal and two at thigh) in four volunteers are considered for the in vivo study. The penetration depths are finally calculated with the help of the electric field distribution in simulations of the optimized model for each one of the 16 considered positions. The numerical results show that positions at the thigh contribute the highest penetration values of up to 17.5 mm. This finding has a high significance in planning in vitro penetration depth measurements and other tests that are going to be performed in the future.
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| 9. |
- Rydberg, Anders, et al.
(författare)
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Theranostic Instrument based on the Combination of Low and High Frequency EM-bio interaction for Bone Defects Analysis and Healing
- 2018
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Ingår i: 2018 EMF-MED 1st World Conference On Biomedical Applications Of Electromagnetic Fields (EMF-MED 2018). - : IEEE. - 9789532900798
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Konferensbidrag (refereegranskat)abstract
- Bone defects due to different diseases and trauma represent a significant health problem. For the follow up on the healing process a sensor which measures the bone mineral density has been developed in the firm of a sensitive split-ring microwave resonator. However, it is not only important to follow up of the healing process but also to find ways of improving the healing, where one way exploited here is to use an externally applied low frequency magnetic field to increase the cell proliferation in the fractured hones. This combines high frequency (microwave) technique with the low frequency (magnetic field) creating a theranostic instrument for clinical and hotneca re applications.
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| 10. |
- Velander, Jacob, et al.
(författare)
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A Four-Layer Phantom for Testing In-Vitro Microwave-Based Sensing Approach in Intra-Cranial Pressure Monitoring
- 2018
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Ingår i: Proceedings Of The 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBioC). - : IEEE. - 9781538659182 ; , s. 49-51
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Konferensbidrag (refereegranskat)abstract
- Multi-layer phantoms in proofs of concept, designs and validations of both microwave-based biomedical sensing and imaging system are becoming popular means to facilitate in-vitro experiments. In addition, they can contribute significantly to reduce animal use in scientific experimentation. In this paper, we design and fabricate a four-layer phantom composed of skin, skull, cerebrospinal fluid and brain mimic tissues to work between 2 and 3 GHz. In addition, the phantom incorporates a mechanism to produce pressure variation between the cerebrospinal fluid and the brain mimic tissues. This phantom is used in an in-vitro experiment to test and validate a new approach which could sense intra-cranial pressure variations through a microwave-based reflection method. The similarity of the phantom's tissues with human tissues from the viewpoint of the microwave response is analyzed in comparison with data from Italian Institute of Applied Physics in Florence. We found good agreement for the dielectric constant (Rel. Err. < 13 % for 68% of significance) in skin, cerebrospinal fluid and brain mimic tissues. For the skin, we got also good agreement for the loss tangent (Rel. Err. < 11 % for 68% of significance). The skull mimic phantom was stiff enough, but even presenting considerable errors, it was still good enough for the experiment. In addition, the capability of the phantom to operate at different pressures is discussed.
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