Electrodynamic system for two-stage THz-generator on the base of two-channel planar FEM A.V. Arzhannikov, N.S. Ginzburg, P.V. Kalinin, N.Yu. Peskov, S.E. Sandalov, S.L. Sinitsky and V.D. Stepanov EPJ Web Conf., 149 (2017) 05017 Published online: 04 August 2017 DOI: 10.1051/epjconf/201714905017