EBG structures to improve the B1 efficiency of stripline coil for 7 Tesla MRI

In: Proceedings of the 6th European Conference on Antennas and Propagation : EuCAP 2012 : Prague, 26-30 March 2012
Piscataway, NJ: IEEE (2012), S. 1399 - 1401
ISBN: 978-1-4577-0918-0, 978-1-4577-0919-7
Buchaufsatz / Kapitel / Fach: Elektrotechnik
Fakultät für Ingenieurwissenschaften » Elektrotechnik und Informationstechnik » Hochfrequenztechnik
This paper presents the first application of an EBG
structure to improve the B1 efficiency of strip-line coils used for 7-Tesla Magnetic Resonance Imaging (MRI). The proposed offset multilayer electromagnetic band gap (EBG) structure is utilized as a high impedance surface behind an extended half-wavelength (meandered) dipole. It operates at 300MHz, the magnetic resonance frequency at 7 T, and comprises of electrically small cells of only 7.5% of the free-space wavelength. The reflection phase coefficient and the dispersion diagram were used to characterize the EBG structure. The MRI strip-line coil backed by our EBG structure is successful in exhibiting a stronger B1-
field inside a phantom than the original design using a metallic conductor (PEC) ground plane for the coil. The quantitative improvement in B1 efficiency amounts to 47%.