Eigenmode analysis of the scattering matrix for the design of MRI transmit array coils

buir.contributor.authorKazemivalipour, Ehsan
buir.contributor.authorSadeghi‐Tarakameh, Alireza
buir.contributor.authorAtalar, Ergin
dc.citation.epage1741en_US
dc.citation.issueNumber3en_US
dc.citation.spage1727en_US
dc.citation.volumeNumber185en_US
dc.contributor.authorKazemivalipour, Ehsan
dc.contributor.authorSadeghi‐Tarakameh, Alireza
dc.contributor.authorAtalar, Ergin
dc.date.accessioned2021-03-31T06:38:55Z
dc.date.available2021-03-31T06:38:55Z
dc.date.issued2021
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.departmentNational Magnetic Resonance Research Center (UMRAM)en_US
dc.description.abstractTo obtain efficient operation modes of transmit array (TxArray) coils using a general design technique based on the eigenmode analysis of the scattering matrix. Methods We introduce the concept of modal reflected power and excitation eigenmodes, which are calculated as the eigenvalues and eigenvectors of SHS, where the superscript H denotes the Hermitian transpose. We formulate the normalized reflected power, which is the ratio of the total reflected power to the total incident power of TxArray coils for a given excitation signal as the weighted sum of the modal reflected power. By minimizing the modal reflected power of TxArray coils, we increase the excitation space with a low total reflection. The algorithm was tested on 4 dual‐row TxArray coils with 8 to 32 channels. Results By minimizing the modal reflected power, we designed an 8‐element TxArray coil to have a low reflection for 7 out of 8 dimensions of the excitation space. Similarly, the minimization of the modal reflected power of a 16‐element TxArray coil enabled us to enlarge the dimension of the excitation space by 50% compared with commonly employed design techniques. Moreover, we demonstrated that the low total reflected power for some critical excitation modes, such as the circularly polarized mode, can be achieved for all TxArray coils even with a high level of coupling. Conclusion Eigenmode analysis is an efficient method that intuitively provides a quantitative and compact representation of the coil’s power transmission capabilities. This method also provides insight into the excitation modes with low reflection.en_US
dc.identifier.doi10.1002/mrm.28533en_US
dc.identifier.eissn1522-2594
dc.identifier.urihttp://hdl.handle.net/11693/76050
dc.language.isoEnglishen_US
dc.publisherInternational Society for Magnetic Resonance in Medicineen_US
dc.relation.isversionofhttps://doi.org/10.1002/mrm.28533en_US
dc.source.titleMagnetic Resonance in Medicineen_US
dc.subjectEigenmode analysisen_US
dc.subjectModal reflected poweren_US
dc.subjectTotal reflected poweren_US
dc.subjectTransmit (TxArray) array coilen_US
dc.titleEigenmode analysis of the scattering matrix for the design of MRI transmit array coilsen_US
dc.typeArticleen_US

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