Alternating Impedance Multi-Channel Transmission Line Resonators for High Field Magnetic Resonance Imaging

In high field MRI systems, microstrip transmission line elements have been successfully implemented as magnetic field generating elements in multi-channel volume coils. However, at these field strengths, short in vivo wavelengths and greater sample losses lead to RF in-homogeneities, as well as, RF inefficiencies. Optimizations of these elements are required to overcome these challenges and to perform a variety of MR applications. In this study, two different microstrip designs with varying impedance lines along the length of the coil - one producing peak magnetic field in the center and the other extending the length of usable magnetic field along the length of the coil- are investigated. Simulation and image results for 8-channel volume coils incorporating these element designs were obtained using a phantom in a 7 Tesla MRI system.