Validating the Narrow-Band Circuit Model for Analysis of the Evanescent Resonant Modes (ERMs)

Evanescent mode oscillators (EMOs) were systematically introduced as high-efficiency sources of millimeter waves and terahertz (THz) oscillations, recently. They use the evanescent resonant mode (ERM) of the slow-wave structures (SWSs). These modes are of basic differences from the modes used in conventional extended interaction oscillators (EIOs). Due to the improved beam-RF interaction efficiency of these modes concerning the conventional ones, an appropriate and rapid analyzing approach is useful to investigate their parameters. A narrow-band circuit model is examined to model the ERM and its nearest higher order competing mode in this article. Outcomes of the circuit model are compared with those of the 3-D electromagnetic analysis for a typical periodic structure, which are seen to be in remarkable agreement. In addition to giving an open eyesight to the formation of the ERMs, the circuit model simulation times can be shortened to the level of several seconds or minutes which is much faster than those of the fully electromagnetic approaches.