The invention discloses a non-introducing
magnetic field compact high-power
microwave device, which comprises an
anode, a
cathode, a coaxial inner conductor, a
coupling plate, and four annular
metal grid meshes, wherein the
anode is provided with an accommodating cavity; the
cathode is connected with the
anode via an insulator and is located in the accommodating cavity; the coaxial inner conductor is connected with the anode and is located in the accommodating cavity, and the coaxial inner conductor and the accommodating cavity form a coaxial structure; the
coupling plate is connected onto the end surface of the coaxial inner conductor; the four annular
metal grid meshes have the same circle center but different semidiameters; the
metal grid meshes are fixedly connected onto a grid mesh supporting area and the coaxial inner conductor; and the four annular
metal grid meshes, the
coupling plate, and the coaxial inner conductor form a
resonant cavity. An
electron beam emission mode is changed into a radial direction, the
metal grid meshes are used for separating the cavity; as the
electron beam is radially emitted, the
electron beam has a large cross section, and a higher beam
current strength can be transmitted in a low
current density condition; and due to the radial structure, the
space charge effects are small, the current limit current is large, input of large beam current can be allowed, and virtual
cathode effects are not generated.