Compact kilowatt millimeter wave source

The invention discloses a compact kilowatt-level millimeter wave source, which comprises an electron gun used for generating cyclotron electron beams, the electron gun is connected with a transition section used for size amplification through an interaction cavity, an output window is arranged at the output end of the transition section, a magnet coil is arranged outside the interaction cavity, and the magnet coil is connected with the electron gun through a power supply. A layer of magnetic steel is arranged outside the magnet coil, the magnetic steel is matched with the interaction cavity to surround the magnet coil, a layer of magnet cooling water cavity is further arranged between the magnet coil and the magnetic steel, and a pipe body cooling water cavity is arranged outside the transition section and the output window. According to the invention, a high-saturation ferromagnetic material is adopted to control a strong magnetic field generated by large current, and a second harmonic gyrotron and a pulse r