Characterization of STELLANT Systems L-4953 Crossed-Field Amplifier via Simulation

Simulation and characterization of the L-4953 Cross-Field Amplifier (CFA) has begun. This is a high power (3.2 kW), moderate gain (11.2 dB), pulsed (1.8 μs), L-band (1.28 to 1.35 GHz), reentrant, backward wave, thermionic cathode amplifier. The goal of this research is to develop a model based on this CFA to study the gain-limiting factors caused by mode interference and test various methods to retain lock on the amplifying mode such as a modulated cathode. This requires a thorough characterization of the device operating under specification, which we present here. Simulations in VSim are used to determine the gain, bandwidth, dispersion, resonant modes and frequencies, zero-drive operation, and particle statistics. At an anode current of, a stable 3 electron spoke operation is observed with the simulated gain matching specification within 1 dB. The dispersion shows backward wave device operation in-between a pair of eigenmodes resembling the TE31 mode. TE41 and TE21 eigenmode pairs are also observed but have lower frequency separation, making these regions less ideal for amplifier operation. Zero-drive simulations show 2, 3, 4, and even 9 electron spoke operation at the previously determined eigenfrequencies. This work will show the device performance, electron population analysis, and results of electron modulation.