power supply system 310 rf signal oscillator generates a continuous rf frequency wave signal 332 at a power level and frequency determined and controlled by micro controller 320 in the embodiment of the present invention the rf signal oscillator 330 is electrically coupled to the power amplifier 334 the power amplifier 334 includes a preamplifier 331 which initially amplifies the wave signal 332 from the rf generator and produces a first train of relatively low energy pulses after amplification by rf amplifier 334 the energy pulses are then delivered via a transmission line 342 to an rf antenna 343 which as been placed in the proximity of the tissue to be ablated as shown in fig2 the bidirectional coupler 336 is electrically interposed between the amplifier 334 and transmission line 342 the coupler samples the relatively low energy forward pulses along the transmission line and the energy pulses reflected from the target ablation tissue and uses the signal samples as feedback to the micro controller 320 the feedback mechanism provided by sampling the signal at the coupler 336 is useful for scaling back the amount of reflected energy too much signal reflection could potentially destroy sensitive system 300 components or cause patient injury electrically in communication with the bi directional coupler 336 the micro controller 320 monitors the forward and reflected energy pulses micro controller 320 then defines a ratio for the.