Aerosol-generating device comprising a resonator with a transmission line

An aerosol-generating device configured to generate aerosol by heating an aerosol-generating material, the aerosol-generating device comprising:

• a cavity configured to receive the aerosol-generating material;
• an electromagnetic field generating unit configured to generate a signal;
• and
• a resonator disposed in the cavity and electrically connected, via at least one feed, to the electromagnetic field generating unit,
• wherein the resonator comprises:
• a first transmission line and a second transmission line, the first and the second transmission lines being configured to receive the generated signal and to generate an electromagnetic field configured to heat the aerosol-generating material, and
• a resonator casing that at least partially surrounds the first and the second transmission lines, and
• wherein each of the first and the second transmission lines includes a first portion and a second portion, a distance between the second portions of the first and the second transmission lines being narrower than a distance between the first portions of the first and the second transmission lines, the at least one feed being arranged at the first portion.