An Antenna Based on Three Coupled Dipoles with Minimized E-field for Ultra-high-field MRI
Loading...
Access rights
openAccess
publishedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Date
Major/Subject
Mcode
Degree programme
Language
en
Pages
10
Series
IEEE Transactions on Antennas and Propagation, Volume 70, issue 10, pp. 9083-9092
Abstract
In this work, we demonstrate an approach for local reduction of the electric field amplitude of the transmitted radio-frequency signal in ultrahigh-field magnetic resonance imaging (MRI). We excite a suitable combination of three coupled dipole hybrid resonances composing a single transmit antenna array element. Using numerical optimization, we designed a feeding network for three coupled dipoles placed over an electromagnetic phantom mimicking a human body. This network of discrete elements provides the appropriate amplitudes and phases of three dipole currents excited by a single input port. It allows controlling the electric field distribution in the vicinity of the antenna. Our goal was to obtain a minimum of the electric field at the given relatively small depth inside the phantom, where body implants are typically located while keeping a tolerable level of the magnetic field toward the phantom's center. We designed and manufactured a three-dipole antenna prototype optimized for MRI of the human body at 7 T (proton Larmor frequency of 298 MHz). The experimental validation showed a 40 dB reduction of the electric field amplitude at a depth of 4 cm compared to a conventional single-dipole antenna. The coupling network can be rearranged to target different depths. Therefore, a principle of electric field minimization at a controllable position inside the body has been shown, which may be useful for designing transmit MRI antennas with improved safety of implants.Description
| openaire: EC/H2020/736937/EU//M-CUBE
Other note
Citation
Balafendiev, R, Solomakha, G, Dubois, M, Abdeddaim, R, Enoch, S, Simovski, C & Glybovski, S 2022, 'An Antenna Based on Three Coupled Dipoles with Minimized E-field for Ultra-high-field MRI', IEEE Transactions on Antennas and Propagation, vol. 70, no. 10, pp. 9083-9092. https://doi.org/10.1109/TAP.2022.3195515