A Radio Frequency (RF) ablation system includes a signal generator, control circuitry, a plurality of non-linear amplifiers, and a processor. The signal generator is configured to generate an RF signal having a given frequency. The control circuitry is configured to set phases and amplitudes of a plurality of replicas of the RF signal generated by the signal generator. The plurality of non-linear amplifiers is configured to amplify the plurality of replicas of the RF signal, and to drive a respective plurality of ablation electrodes in a patient body with the amplified replicas. The processor is configured to receive a return signal, including a superposition of the replicas sensed by a patch electrode attached to the patient body, and to adaptively adjust the phases and amplitudes of the replicas in response to the return signal, by controlling the control circuitry.
