High-efficiency subnanosecond microwave pulse generation in a relativistic backward wave tube

Abstract

The regime of nonstationary oscillations with a short-time power burst, which is typical of the initial stage of a transient process developed when a beam current significantly exceeds the starting level, is studied in a relativistic backward wave tube (BWT) operating in the millimeter wavelength range. The results of numerical calculations allowed conditions to be established that provide for a nearly 90% efficiency of the power transfer from an electron beam with the parameters 300 keV, 2 kA, 1 ns to the microwave pulse with a duration of 8–10 periods of the microwave field oscillations. The experiments showed the possibility of generating such pulses with a width of 200–250 ps and a power of up to ∼400 MW at a central frequency of about 38 GHz.