Characterizing the high-power-microwaves radiated by an axial output compact S-band A6 segmented magnetron fed by a split cathode and powered by a linear induction accelerator

Abstract

In a recent publication [J. Appl. Phys. 131, 023301 (2022)], microwave generation by a segmented A6 S-band axial output relativistic magnetron (RM) fed by a split cathode and powered by a small pulsed power generator was demonstrated for the first time. In the present article, we add to the same RM a mode converter and an antenna and drive it by using a modified linear induction accelerator (LIA) (≤450 kV, ≤4 kA, ∼150 ns). It was found that the operation of the RM for a split cathode or a common explosive emission cathode differs significantly. For a split cathode, we optimize for the best microwave output, its geometrical parameters, the external magnetic field, and the LIA's charging voltages. For the optimal choice of these parameters, the RM generates ∼160 ns long microwave pulses of ∼130 MW, 1.78 GHz frequency with an electronic efficiency of ∼40%, without pulse shortening. On the other hand, a common solid cathode fed RM showed microwave pulse shortening. We demonstrated that the segmented anode allows using a μs-timescale magnetic field, making it possible for the RM to operate repetitively.