The compact excitation module comprises two radiofrequency RF exciters and a rotary joint coupled together along a common longitudinal axis, the rotary joint comprising two distinct parts, respectively fixed and rotating around the common longitudinal axis, the two radiofrequency exciters being mounted one on each side of the rotary joint, respectively on the fixed and rotating parts, and axially coupled together by the rotary joint. The compact excitation module further comprises a rotary actuator provided with an axial transverse opening, the rotary joint being housed in the axial transverse opening of the rotary actuator.