A Way to Match the Second Symmetric Mode of Double-Grid Slow Wave Structure for Terahertz BWO

In this paper, a way to match the second symmetric mode of double-grid slow wave structure designed for a practical 1-THz terahertz backward wave oscillator is presented. Simulation results show that the return loss is less than -15 dB, and the insertion loss is about -4 dB in the 50-GHz operating bandwidth.