Relativistic Sub-THz Surface-Wave Sheet-Beam Amplifier With Transverse Energy Input and Output

We propose a high-power extended interaction klystron (EIK) amplifier exploiting open gratings as surface-wave cavities driven by a relativistic high-current sheet electron beam. For in- and out-coupling of the radiation, an additional subharmonic corrugation with a period twice larger than the period of the grating is proposed. Simulations based on both averaged quasi-optical model and particle-in-cell (PIC) code demonstrate the feasibility of the 150-GHz amplifier with 20–40-MW output power and 20–30-dB linear gain in 1% bandwidth.