The invention discloses a K-waveband coaxial relativistic
backward wave oscillator. The oscillator comprises positive
electrode, a negative
electrode, an
electron beam guide grid mesh and a coaxial inner conductor, wherein the positive
electrode is a
cylindrical waveguide cavity containing a slow-
wave structure; the negative electrode is arranged in the
cylindrical waveguide cavity and connected with one end plane of the positive electrode through an insulator; the
electron beam guide grid mesh is arranged in the
cylindrical waveguide cavity and positioned in the downstream of the
electron transmitting end of the negative electrode; the coaxial inner conductor adopts a cylindrical structure; one end of the coaxial inner conductor is arranged in the cylindrical
waveguide cavity while the other end of the coaxial inner conductor is connected with the other end plane of the positive electrode through a
metal bracket; and a coaxial structure is formed by the coaxial inner conductor, the negative electrode and the cylindrical
waveguide cavity. According to the K-waveband coaxial relativistic
backward wave oscillator, the electron beam guide grid mesh with the electron beam
transmittance of greater than 90% is adopted for guiding electron beams to enter a beam interaction region, so that the required external
magnetic field intensity is lowered, the guide
magnetic field required by a device is reduced to 0.5T, the huge size of the guide
magnetic field system on the exterior of the device is reduced, and requirement on the
energy source supply is reduced.