Compact and High-Efficiency Magnetron With All-Cavity Diffraction Output

A compact and high-efficiency magnetron with diffraction output is proposed. In this diffraction output configuration, all cavities are tapered onto the horn antenna to extract the RF field of the operating <tex-math notation="LaTeX">π</tex-math> mode from every resonator cavity and convert it to the TE <tex-math notation="LaTeX">₀₁</tex-math> mode for high output power. To demonstrate the capability, an <tex-math notation="LaTeX">S</tex-math> -band ten-cavity magnetron with all-cavity diffraction output is designed. Compared to the conventional design, the cutoff radius of the TE <tex-math notation="LaTeX">₀₁</tex-math> mode is smaller than the TE <tex-math notation="LaTeX">₅₁</tex-math> mode in the circular waveguide. Consequently, the diameter of the output waveguide can be reduced significantly. Moreover, the short length of the diffraction output, about 0.63 <tex-math notation="LaTeX">λ</tex-math> ( <tex-math notation="LaTeX">λ</tex-math> is the operation wavelength), is designed to further reduce the volume of the proposed magnetron. Simulation results show that the proposed magnetron generates 3.64 MW output power with a power conversion efficiency of 91% at 2.31 GHz when the applied voltage is 46 kV and the axial magnetic field is 0.2 T.