| CPC A61B 18/1815 (2013.01) [H02M 3/155 (2013.01); H03F 3/21 (2013.01); A61B 2018/00702 (2013.01); A61B 2018/1861 (2013.01)] | 23 Claims |

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1. A microwave amplification apparatus for an electrosurgical instrument, the microwave amplification apparatus comprising:
a cable assembly;
a proximal launch portion connected to a proximal end of the cable assembly, the proximal launch portion comprising:
a DC source configured to launch a DC signal along the cable assembly; and
a microwave source configured to launch a microwave signal along the cable assembly;
a distal amplification portion connected to a distal end of the cable assembly, the distal amplification portion comprising a power amplifier configured to receive the microwave signal as an input signal to be amplified,
wherein the distal amplification portion is configured to apply the DC signal as a drain voltage across the power amplifier; and
a gate voltage extraction module configured to extract a bias voltage from the DC signal and apply it to a gate of the power amplifier;
wherein the power amplifier has an output that is connectable to deliver an amplified microwave signal to a structure that is configured to deliver microwave energy into biological tissue; and
wherein the gate voltage extraction module is configured to extract a pair of bias voltages from the DC signal, wherein the pair of bias voltages comprises a first bias voltage corresponding to a non-conducting state of the power amplifier, and a second bias voltage corresponding to a conducting state of the power amplifier.
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