An electrosurgical generator for generating radiofrequency (RF) electromagnetic (EM) energy and microwave EM energy comprises: a microwave source for generating a microwave signal； a microwave channel for conveying the microwave signal from the microwave source to be output from the generator； an RF channel for conveying an RF signal to be output from the generator； and a microwave-to-RF converter connectable to receive the microwave signal, the microwave-to-RF converter being arranged to: generate the RF signal from the microwave signal, and deliver the RF signal to the RF channel.
