Oversized W-band 2D Periodic Lattice Oscillator

To mitigate the conventional scaling of slow-wave vacuum electronic oscillators, in which the maximum output power reduces as the frequency increases, an oversized cylindrical structure is driven by an annular electron beam. To enhance mode selectivity a two dimensional (2D) periodic lattice structure (PSL) is used. The 2D PSL consists of shallow periodic cosinusoidal perturbations in both the azimuthal and axial directions on the inner wall of a cylindrical waveguide. Analytical theory and numerical PIC simulations have been used to design the W-band oscillator that has been constructed. The ratio of the diameter of the cylindrical cross-section of the structure to the operating wavelength is ~5. The performance of this oscillator is being measured and compared with the predictions of the numerical simulations.