Parallel multi-beam and its application in THz band

A conception of parallel multi-beam is proposed for vacuum devices in THz band. This multi-beam, combined with the planar geometry of parallel pins circuit, can be applied in 300GHz-500GHz band. We have identified stable multi-beam formation and transport as the key enabling technology for this type of device. The convergence and control of this multi-beam is investigated by an elliptical solenoidal magnetic field. The dispersion of the slow-wave structure (SWS) is studied and compared with that of conventional corrugated waveguide SWS. Also, the interaction impedance in beam tunnel is calculated. The result shows that the structure has high interaction impedance suitable for this type of parallel multiple beams. To demonstrate these characteristics, two types of BWO at the central frequency of 340 GHz and 520GHz with 4-beam and the circuit of 3-row pins are studied by 3-D particle-in-cell simulation. Results indicate that this multi-beam combined with the planar geometry can lead to high-peak power output with low operation current of each beam and greater allowable total beam current.