A method of making a compact control module of a high frequency antenna for a magnetic resonance imaging device including M control elements and N radiating elements, N greater than M, the control module represented by a control matrix {tilde over (P)}, approximately equal to a control matrix P to control the radiating elements, the method including: decomposing the control matrix {tilde over (P)} into a product of two matrices H×L; the matrix L with dimensions M×M capable of transforming M signals Vm transmitted by M control elements into M signals Vl, in amplitude and in phase; the matrix H with dimensions N×M receiving the M signals Vl as inputs; producing the matrix FI with a number of stages less than a number of stages necessary for implementation of the matrix P; and using the matrix L starting from implementation of the matrix H determined during the producing.