Abstract: For coupling RF energy into a piezoelectric transducer, a sheet of conductive foil is held in pressure contact with substantially the entire surface of a transducer electrode. A heat sink is thermally coupled to the sheet of conductive foil through a layer of material that is electrically insulative and also effectively thermally conductive so as to draw heat away from the transducer. Moreover, this layer of material that is interposed between the heat sink and the sheet of conductive foil has the property of creating an acoustic impedance mismatch between the transducer and the heat sink, so that acoustic waves that are launched by the transducer will not be transmitted into the heat sink, but will be confined to the intended medium of acoustic propagation upon which the transducer is mounted.