Analysis of mode excitation of a relativistic magnetron with azimuthal-periodic-cavity extraction

Relativistic magnetron (RM) with all cavity-magnetron axial extraction (ACMAE) has attracted much attention, benefiting from its good performance. In this paper, RM with ACMAE is generalized to a general case called RM with azimuthal-periodic-cavity extraction due to the introduction of two structure parameters of R and S, where R indicates the number of cavities between the two extraction cavities in a coupling waveguide and S indicates the number of cavities between two adjacent coupling waveguides. The necessary conditions for mode excitation of the RM are theoretically investigated and verified by simulations. Using the expression of the necessary conditions, one can easily figure out the output mode components of the RM in theory according to the structural parameters and the number of electron spokes. This new technique provides more solving schemes with different extraction structures for designing high performance RMs with different advantages in applications of high power microwave.