9.4 T double‐tuned 13 C/ 1 H human head array using a combination of surface loops and dipole antennas

Dipole-Fed Rectangular Dielectric Resonator Antennas for Magnetic Resonance Imaging at 7 T: The Impact of Quasi-Transverse Electric Modes on Transmit Field Distribution

Frontiers in Physics ◽

10.3389/fphy.2021.675509 ◽

2021 ◽

Vol 9 ◽

Author(s):

Daniel Wenz ◽

Rolf Gruetter

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Field Distribution ◽

Human Head ◽

Dipole Antenna ◽

Resonance Imaging ◽

Dipole Antennas ◽

Rectangular Block ◽

The Impact

Shortened dipole antennas based on rectangular dielectric blocks play an important role in ultrahigh field magnetic resonance imaging (UHF-MRI) radio frequency (RF) coil design. However, the generally assumed direct contact with the subject is difficult to maintain in typical in vivo settings. We have previously observed that certain dielectrically shortened dipole antennas can produce a substantially altered transmit field distribution with a very low transmit efficiency when the block and the sample are physically separated. Therefore, the aim of this study was to determine a) why certain designs of dielectrically shortened dipole antennas can produce an inefficient transmit field when the block and the sample are physically separated and b) how this depends on key parameters such as rectangular block geometry, dielectric constant, loading geometry, and RF feeding. In this work, two main types of quasi-transverse dielectric modes were found in different rectangular block geometries and interpreted as TE11δz (MR efficient) and TE1δδy (MR inefficient), and their impact on in vivo MRI experiments involving the human head, calf, and wrist was explored. This study shows, for the first time, why certain antennas preserve their transmit field efficiency despite physical separation from the sample. We conclude that the proposed approach has the potential to provide new insights into dipole antenna design for UHF-MRI.

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A 16-channel transceiver loop+dipole antennas head array for human head imaging at 10.5T

2017 International Conference on Electromagnetics in Advanced Applications (ICEAA) ◽

10.1109/iceaa.2017.8065607 ◽

2017 ◽

Cited By ~ 2

Author(s):

Myung Kyun Woo ◽

Russell L Lagore ◽

Lance DelaBarre ◽

Byeong-Yeul Lee ◽

Yigitcan Eryaman ◽

...

Keyword(s):

Human Head ◽

Dipole Antennas

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SAR analysis of tri-band antennas for a 5G eyewear device

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078720000173 ◽

2020 ◽

Vol 12 (8) ◽

pp. 754-761

Author(s):

M. Dilruba Geyikoğlu ◽

Hilal Koç Polat ◽

Fatih Kaburcuk ◽

Bülent Çavuşoğlu

Keyword(s):

Absorption Rate ◽

Specific Absorption Rate ◽

High Dielectric Constant ◽

Human Head ◽

3D Printer ◽

Dipole Antennas ◽

Device Applications ◽

Simulation Results ◽

High Dielectric ◽

Sar Analysis

AbstractThe goal of this study is to analyze the specific absorption rate (SAR) distribution of the projected 5G frequencies below 6 GHz and at Wi-Fi frequency (2.45 GHz) on a human head, for eyewear device applications. Two separate tri-band printed dipole antennas for this purpose are designed and fabricated at operating frequencies of 2.45/3.8/6 GHz for prototype-1 and at operating frequencies of 2.45/3.6/4.56 GHz for prototype-2. In order to obtain the desired frequencies: first, the prototypes of the proposed antennas are fine-tuned via Computer Simulation Technology Microwave Studio (CST) and then fabricated on the FR4 layer. The reflection coefficient (S11) is tested and the simulation results are confirmed. In order to analyze the effect of wearing a pair of glasses' frame including a tri-band 5G antenna, a frame is designed and produced via 3D printer with polylactic acid material which has high dielectric constant (ɛr = 8.1). The SAR results of the proposed antennas have been examined for the cases where the antenna is embedded in the frame and is used alone. Both cases were analyzed by using the homogeneous specific anthropomorphic mannequin and the heterogeneous visible human head phantoms and the results have been evaluated in terms of SAR10 g values.

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Evaluation of short folded dipole antennas as receive elements of ultra‐high‐field human head array

Magnetic Resonance in Medicine ◽

10.1002/mrm.27754 ◽

2019 ◽

Vol 82 (2) ◽

pp. 811-824 ◽

Cited By ~ 3

Author(s):

Nikolai I. Avdievich ◽

Georgiy Solomakha ◽

Loreen Ruhm ◽

Klaus Scheffler ◽

Anke Henning

Keyword(s):

High Field ◽

Human Head ◽

Dipole Antennas ◽

Ultra High Field ◽

Folded Dipole

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MOLECULAR STUDY OF HUMAN HEAD LICE, PEDICULUS HUMANUS CAPITIS COMPARISON WITH GOAT SUCKING LICE, LINOGNATHUS STENOPSIS (BURMEISTER) STRAINS

Anbar Journal of Agricultural Sciences ◽

10.32649/ajas/2020/12 ◽

2020 ◽

pp. 132-139

Keyword(s):

Genetic Difference ◽

Human Head ◽

Molecular Study ◽

Head Lice ◽

Pediculus Humanus Capitis ◽

School Students ◽

Pediculus Humanus ◽

Sucking Lice ◽

Pcr Products ◽

Amplicon Size

In this study, only (122) out of (915) primary school students were shown to be infected with head lice Pediculus. humanus capitis. The number and percentage of infected males were 46 (11.3%), while the number and percentage of infected females were 76 (14.9%). The results in our study also showed that the number and percentage of goats infected with goat sucking lice, Linognathus stenopsis was 70 (21.7%) of the total 322 animals, with the highest number and percentage among female goats 44 (62.9%) compared to the male goats 26 (37.1%). The study demonstrated that the rate of genetic difference between the studied samples was 89% and the similarity rate was 11%. Detection of OP-K01 gene pieces by PCR products showed that the amplicon size was 520 bp for P. humanus capitis isolated from humans, while the detection of OP-E20 and OP-M05 gene pieces with PCR product showed the lowest amplicon size 230 bp for Linognathus stenosis isolated from goats.

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