Abstract
The radial transit time oscillator (RTTO) has attracted much attention because of its high power capacity and pure mode of output microwave. To make the high power microwave (HPM) source devices more compact and to enable it to measure the output microwave mode quantitatively, this paper proposed a compact Ku-band RTTO with the power divider extraction structure (PDES). The radial decreasing magnetic field is applied to decreasing the mass of excitation system. Compared the conventional uniform solenoids, it can reduce the mass by about 30%. In the coaxial output waveguide, the PDES is used instead of the traditional support rods connecting the inner and outer conductors so as to convert TEM mode into TE10 mode efficiently. This structure can not only help shorten the axial dimension of the device, but also make it possible to measure the output microwave mode more accurately online. In particle-in-cell (PIC) simulation, the proposed Ku-band RTTO can output HPMs with the power of 3.05 GW and the frequency of 14.36 GHz, and the working efficiency is 40.3%. The maximum radial electric field intensity in the extraction cavity is 0.92 MV/cm, and the maximum electric field intensity in the PDES is 0.52 MV/cm, both of which are lower than the radio frequency (RF) breakdown threshold of metal materials.
Design of Ku-band power divider using Substrate Integrated Waveguide technique