Design of Implantable Antennas for Medical Telemetry

Implantable Medical Devices (IMDs) with wireless telemetry functionalities in the radio-frequency (RF) range are recently attracting significant scientific interest for medical prevention, diagnosis, and therapy. One of the most crucial challenges for IMDs is the design of the integrated implantable antenna which enables bidirectional wireless communication between the IMD and exterior monitoring/control equipment. In this paper, a parametric model of a miniature implantable antenna is initially proposed, which can be adjusted to suit any antenna design and implantation scenario requirements in hand. Dependence of the resonance, radiation, and safety performance of implantable antennas upon (a) operation frequency, (b) tissue anatomy and dielectric properties, and (c) implantation site is further studied. Simulations are carried out: (a) at 402, 433, 868 and 915 MHz considering a 13-tissue anatomical head model, (b) at 402 MHz considering five head models (3- and 5-layer spherical, 6-, 10- and 13-tissue anatomical) and seven dielectric parameter scenarios (variations ±20% in the reference permittivity and conductivity values), and (c) at 402 MHz considering 3-layer canonical models of the human head, arm, and trunk. The study provides valuable insight into the design of implantable antennas. Finite Element and Finite Difference Time Domain numerical solvers are used.

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Efficient Electromagnetic Analysis of a Dispersive Head Model Due to Smart Glasses Embedded Antennas at Wi-Fi and 5G Frequencies

Applied Computational Electromagnetics Society ◽

10.47037/2020.aces.j.360207 ◽

2021 ◽

Vol 36 (2) ◽

pp. 159-167

Author(s):

Fatih Kaburcuk ◽

Atef Elsherbeni

Keyword(s):

Numerical Study ◽

Computation Time ◽

Human Head ◽

Head Model ◽

Computer Memory ◽

Large Computer ◽

Smart Glasses ◽

Embedded Antennas ◽

Human Head Model ◽

Difference Time

Numerical study of electromagnetic interaction between an adjacent antenna and a human head model requires long computation time and large computer memory. In this paper, two speeding up techniques for a dispersive algorithm based on finite-difference time-domain method are used to reduce the required computation time and computer memory. In order to evaluate the validity of these two speeding up techniques, specific absorption rate (SAR) and temperature rise distributions in a dispersive human head model due to radiation from an antenna integrated into a pair of smart glasses are investigated. The antenna integrated into the pair of smart glasses have wireless connectivity at 2.4 GHz and 5th generation (5G) cellular connectivity at 4.9 GHz. Two different positions for the antenna integrated into the frame are considered in this investigation. These techniques provide remarkable reduction in computation time and computer memory.

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Small Triple-Band Meandered PIFA for Brain-Implantable Biotelemetric Systems: Development and Testing in a Liquid Phantom

International Journal of Antennas and Propagation ◽

10.1155/2021/6035169 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Nikta Pournoori ◽

Lauri Sydänheimo ◽

Yahya Rahmat-Samii ◽

Leena Ukkonen ◽

Toni Björninen

Keyword(s):

State Of The Art ◽

Data Communication ◽

Human Head ◽

The Body ◽

Head Model ◽

Wireless Power ◽

Wireless Data ◽

Full Wave ◽

Implantable Antennas ◽

Triple Band

We present a meandered triple-band planar-inverted-F antenna (PIFA) for integration into brain-implantable biotelemetric systems. The target applications are wireless data communication, far-field wireless power transfer, and switching control between sleep/wake-up mode at the Medical Device Radiocommunication Service (MedRadio) band (401–406 MHz) and Industrial, Scientific and Medical (ISM) bands (902–928 MHz and 2400–2483.5 MHz), respectively. By embedding meandered slots into the radiator and shorting it to the ground, we downsized the antenna to the volume of 11 × 20.5 × 1.8 mm3. We optimized the antenna using a 7-layer numerical human head model using full-wave electromagnetic field simulation. In the simulation, we placed the implant in the cerebrospinal fluid (CSF) at a depth of 13.25 mm from the body surface, which is deeper than in most works on implantable antennas. We manufactured and tested the antenna in a liquid phantom which we replicated in the simulator for further comparison. The measured gain of the antenna reached the state-of-the-art values of −43.6 dBi, −25.8 dBi, and −20.1 dBi at 402 MHz, 902 MHz, and 2400 MHz, respectively.

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Assessment of specific absorption rate reduction in human head using metamaterial

Science and Engineering of Composite Materials ◽

10.1515/secm-2013-0044 ◽

2014 ◽

Vol 21 (1) ◽

pp. 79-85 ◽

Cited By ~ 3

Author(s):

Mohammad Rashed Iqbal Faruque ◽

Mohammad Tariqul Islam ◽

Nik Abdullah Nik Mohamed

Keyword(s):

Absorption Rate ◽

Specific Absorption Rate ◽

Structural Parameters ◽

Fdtd Method ◽

Human Head ◽

Ring Resonators ◽

Specific Absorption ◽

Difference Time ◽

Communication Equipment ◽

Insight Into

AbstractIn this paper, the specific absorption rate (SAR) reduction in human head with metamaterial attachment is calculated. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in an anatomically correct model of the human head. We designed the double-negative metamaterials by placing periodic array arrangement of split ring resonators (SRRs). By properly designing and tuning the structural parameters of SRRS, the effective medium parameters can be made negative at 900 and 1800 MHz band, as presented in this paper. Experimental results show that, with presence of resonators, SAR reduction in the human head is achievable. These results can provide useful insight into the design of safety-compliant mobile communication equipment.

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Bio-implantable Antenna at Human Head Model

2019 International Conference on Robotics,Electrical and Signal Processing Techniques (ICREST) ◽

10.1109/icrest.2019.8644333 ◽

2019 ◽

Cited By ~ 1

Author(s):

Md. Nizam Uddin ◽

Raja Rashidul Hasan ◽

Md. Abdur Rahman ◽

Shantanu Kumar Nath ◽

Palash Sarkar

Keyword(s):

Human Head ◽

Head Model ◽

Implantable Antenna ◽

Human Head Model

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Evaluation of specific absorption rate and temperature elevation in a multi-layered human head model exposed to radio frequency radiation using the finite-difference time domain method

IET Microwaves Antennas & Propagation ◽

10.1049/iet-map.2010.0172 ◽

2011 ◽

Vol 5 (9) ◽

pp. 1073 ◽

Cited By ~ 16

Author(s):

A.I. Sabbah ◽

N.I. Dib ◽

M.A. Al-Nimr

Keyword(s):

Time Domain ◽

Finite Difference Time Domain ◽

Absorption Rate ◽

Specific Absorption Rate ◽

Human Head ◽

Head Model ◽

Temperature Elevation ◽

Radio Frequency Radiation ◽

Difference Time ◽

Frequency Radiation

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Study of the resistor material of an automotive spark plug by use of the charge-up effect along with elemental mapping in an electron microprobe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088026 ◽

1991 ◽

Vol 49 ◽

pp. 742-743

Author(s):

D. R. Liu ◽

S. S. Shinozaki ◽

J. S. Park ◽

B. N. Juterbock

Keyword(s):

Electron Microprobe ◽

Present Report ◽

Coated Sample ◽

Valuable Insight ◽

Elemental Mapping ◽

Spark Plug ◽

Carbon Coated ◽

Electron Image ◽

Electron Imaging ◽

Insight Into

The electric and thermal properties of the resistor material in an automotive spark plug should be stable during its service lifetime. Containing many elements and many phases, this material has a very complex microstructure. Elemental mapping with an electron microprobe can reveal the distribution of all relevant elements throughout the sample. In this work, it is demonstrated that the charge-up effect, which would distort an electron image and, therefore, is normally to be avoided in an electron imaging work, could be used to advantage to reveal conductive and resistive zones in a sample. Its combination with elemental mapping can provide valuable insight into the underlying conductivity mechanism of the resistor.This work was performed in a CAMECA SX-50 microprobe. The spark plug used in the present report was a commercial product taken from the shelf. It was sectioned to expose the cross section of the resistor. The resistor was known not to contain the precious metal Au as checked on the carbon coated sample. The sample was then stripped of carbon coating and re-coated with Au.

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Quantum Mechanical Interpretation of the Ultra-Low Energy Methyl-Rotation Dynamics in Porous Metal-Organic Frameworks Probed by Low-Frequency Vibrational Spectroscopy and ab initio Simulations

10.26434/chemrxiv.5995078.v1 ◽

2018 ◽

Author(s):

Qi Li ◽

Adam J. Zaczek ◽

Timothy M. Korter ◽

J. Axel Zeitler ◽

Michael T. Ruggiero

Keyword(s):

Ab Initio ◽

Metal Organic Frameworks ◽

Low Frequency ◽

Rotor Dynamics ◽

Quantum Mechanical ◽

Valuable Insight ◽

Void Space ◽

Ab Initio Simulations ◽

Metal Organic ◽

Insight Into

<div>Understanding the nature of the interatomic interactions present within the pores of metal-organic frameworks</div><div>is critical in order to design and utilize advanced materials</div><div>with desirable applications. In ZIF-8 and its cobalt analogue</div><div>ZIF-67, the imidazolate methyl-groups, which point directly</div><div>into the void space, have been shown to freely rotate - even</div><div>down to cryogenic temperatures. Using a combination of ex-</div><div>perimental terahertz time-domain spectroscopy, low-frequency</div><div>Raman spectroscopy, and state-of-the-art ab initio simulations,</div><div>the methyl-rotor dynamics in ZIF-8 and ZIF-67 are fully charac-</div><div>terized within the context of a quantum-mechanical hindered-</div><div>rotor model. The results lend insight into the fundamental</div><div>origins of the experimentally observed methyl-rotor dynamics,</div><div>and provide valuable insight into the nature of the weak inter-</div><div>actions present within this important class of materials.</div>

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A Review of Phytochemical and Pharmacological Studies of Inula Species

Current Bioactive Compounds ◽

10.2174/1573407215666190207093538 ◽

2020 ◽

Vol 16 (5) ◽

pp. 557-567

Author(s):

Aparoop Das ◽

Anshul Shakya ◽

Surajit Kumar Ghosh ◽

Udaya P. Singh ◽

Hans R. Bhat

Keyword(s):

Bacterial Infections ◽

Chemical Constituents ◽

Valuable Insight ◽

Important Ingredient ◽

Pharmacological Activities ◽

Medicinal Uses ◽

The Family ◽

Pharmacological Studies ◽

Perennial Herbs ◽

Insight Into

Background: Plants of the genus Inula are perennial herbs of the family Asteraceae. This genus includes more than 100 species, widely distributed throughout Europe, Africa and Asia including India. Many of them are indicated in traditional medicine, e.g., in Ayurveda. This review explores chemical constituents, medicinal uses and pharmacological actions of Inula species. Methods: Major databases and research and review articles retrieved through Scopus, Web of Science, and Medline were consulted to obtain information on the pharmacological activities of the genus Inula published from 1994 to 2017. Results: Inula species are used either alone or as an important ingredient of various formulations to cure dysfunctions of the cardiovascular system, respiratory system, urinary system, central nervous system and digestive system, and for the treatment of asthma, diabetes, cancers, skin disorders, hepatic disease, fungal and bacterial infections. A range of phytochemicals including alkaloids, essential and volatile oils, flavonoids, terpenes, and lactones has been isolated from herbs of the genus Inula, which might possibly explain traditional uses of these plants. Conclusion: The present review is focused on chemical constituents, medicinal uses and pharmacological actions of Inula species and provides valuable insight into its medicinal potential.

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Neural silences can be localized rapidly using noninvasive scalp EEG

Communications Biology ◽

10.1038/s42003-021-01768-0 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Alireza Chamanzar ◽

Marlene Behrmann ◽

Pulkit Grover

Keyword(s):

Center Of Mass ◽

Cost Effective ◽

Human Head ◽

Head Model ◽

Cortical Function ◽

Scalp Eeg ◽

Localization Algorithms ◽

Important Benefit ◽

Eeg Recordings ◽

Detection And Localization

AbstractA rapid and cost-effective noninvasive tool to detect and characterize neural silences can be of important benefit in diagnosing and treating many disorders. We propose an algorithm, SilenceMap, for uncovering the absence of electrophysiological signals, or neural silences, using noninvasive scalp electroencephalography (EEG) signals. By accounting for the contributions of different sources to the power of the recorded signals, and using a hemispheric baseline approach and a convex spectral clustering framework, SilenceMap permits rapid detection and localization of regions of silence in the brain using a relatively small amount of EEG data. SilenceMap substantially outperformed existing source localization algorithms in estimating the center-of-mass of the silence for three pediatric cortical resection patients, using fewer than 3 minutes of EEG recordings (13, 2, and 11mm vs. 25, 62, and 53 mm), as well for 100 different simulated regions of silence based on a real human head model (12 ± 0.7 mm vs. 54 ± 2.2 mm). SilenceMap paves the way towards accessible early diagnosis and continuous monitoring of altered physiological properties of human cortical function.

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