| Two objectives are addressed in this thesis. First is the design and construction of a customized transmission hardware solution for the purpose of assembling a multi-channel transmission array. We demonstrate how a current-mode class-D amplifier and accompanying electronics form a system with high power, efficiency, decoupling, and scalability features. Second is application of this hardware for outstanding problems in clinical MRI, specifically to correction of problems B0 variations create and reduction of coupling to long conductors, such as are found in implanted medical devices. We show that an array of transmission elements can address both of these concerns, through thoughtful selection of the fields that each element produces by capitalizing on their intrinsic frequency, amplitude, and phase degrees of freedom. |
