PIC Simulations of an S-Band Surface Wave Microwave Oscillator Using a Two-Spiral Metamaterial Structure

Recently many researchers have been studying metamaterial (MTM)-based high power microwave (HPM) sources (see [1] and references therein). We developed a new two-spiral MTM unit celles. Several unit cells are combined to form a slow wave structure in a cylinder with a beam collector at the end. PIC simulation with negative $\varepsilon$ in S-band which is constructed from two parallel metallic plates demonstrate that when a 0.8 MeV, 84 A electron beam propagates through this structure with an applied magnetic field varying from 0.05 T to 0.2 T, the surface wave of TM 01 mode is generated at 3.18 GHz with an output power of 17 MW and electronic efficiency as high as 26%. When we optimized the beam energy and beam current, an output power of 77 MW with electronic efficiency as high as 51% can be obtained while the output spectrum has some small mode competition. This research can represent a new direction for the development of high-efficiency HPM devices.