Analysis of Coupling and Loading in RF Coils for Magnetic-Resonance Imaging

摘要

In this contribution generalized field-theoretical and circuit-based analyses of field distribution and element coupling and loading in MRI-RF coils are presented and/or revisited. They are applicable to high-field operations, in which the geometrical dimensions of the coil become comparable to the Larmor wave-length. The circuit-based analysis utilizes the characteristic properties of circulant matrices that describe periodic structures with ring-type coupling. It allows for controlling the coupling without the need of minimizing or eliminating it. It also gives useful equations for the calculation of the coil loading, which is needed for the optimization of its operation in both transmitting and receiving scenarios. The paper is essentially of a fundamental nature and presents and/or revisits physical insights and useful equations. Therefore, no simulation or measurement results are included.