AbstractOptimization of an antenna for magnetic resonance imaging (MRI) requires an accurate analysis of antennas located inside a conducting cylindrical RF shield. A Galerkin‐moment method analysis which can be used for an arbitrary‐shaped shield is used. The surface current on a conducting plane is expanded by means of surface patch segments based on Richmond's method. Numerical results are compared with measured input impedance, which confirms the validity of the proposed method. Furthermore, a relation between the dimension of shield and the sensitivity of the antenna is discussed theoretica