An MRI apparatus and method is disclosed comprising a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images. The RF coil assembly comprises an RF tube, a plurality of electrically conductive members disposed around the RF tube and configured to transmit RF excitation pulses, a plurality of electrical components coupled to the electrically conductive members, and at least one thermally conductive substrate mounted upon the RF tube, wherein one of the plurality of electrically conductive members and the plurality of electrical components is mounted to the at least one thermally conductive substrate and is in thermal contact therewith.