Preliminary Study of a Sub-Terahertz Orthogonal Grating Waveguide for High-Order Mode Backward Wave Oscillators

The preliminary design of a sub-terahertz high-order mode (HOM) orthogonal grating waveguide (OGW) for multiple sheet-beam backward wave oscillators (BWOs) is presented in this paper. The dispersion characteristic of HOM OGW is simulated by using the Eigenmode Solver of the Computer Simulation Technology (CST). A 100-period OGW circuit is simulated, which indicates that the transmission and reflection coefficients are above -2 dB and below -10 dB in the frequency range of 168.8-223.2 GHz, respectively.