Electrosurgical system for identifying and treating biological tissue

An electrosurgical generator comprising:

• an electromagnetic signal supply unit for generating electromagnetic, EM, energy to be conveyed along each of a plurality of channels, wherein each of the plurality of channels is arranged to convey electromagnetic energy at a different frequency, wherein the plurality of channels includes a first channel arranged to convey electromagnetic energy at a first frequency, and a second channel arranged to convey electromagnetic energy at a second frequency that is different from the first frequency;
• an output port selectively connectable to each of the plurality of channels, wherein the output port is configured to be connectable to an electrosurgical instrument for delivering the electromagnetic energy to biological tissue;
• a tissue identification unit comprising a controller configured to:
• detect, from each of the plurality of channels, a signal indicative of a load impedance at the output port;
• detect a phase offset from energy conveyed on the second channel;
• determine a set of complex impedance values from the detected signals, wherein the set of complex impedance values comprises a complex impedance value for the load at each of the first frequency and the second frequency;
• apply the phase offset when determining the complex impedance value for the load at the first frequency;
• identify a tissue type from the set of complex impedance values;
• and
• generate an output for communicating the identified tissue type to a user;
• wherein the electrosurgical generator further comprises:
• a flexible transmission line connected to the output port for conveying the electromagnetic energy to the electrosurgical instrument;
• and
• a selectively reflective element mounted at a distal end of the flexible transmission line,
• wherein the selectively reflective element has an electrical length that is an odd multiple quarter wavelength at the second frequency, and a multiple half wavelength at the first frequency.