Investigations on Dispersion and Gain in Nonstaggered Bilateral Metal-Grating Periodic Structure With Electron Beam

A linear theory of a nonstaggered bilateral metal-grating periodic slow-wave structure with a sheet electron beam is developed using the Borgnis potential function and field-matching method. The field-matching method has been used at the upper and bottom waveguide boundaries where the metal-grating structure is used to slow down the electromagnetic phase velocity. The derived dispersion equation has been solved through the iterative technique. Numerical calculations show the effects of some parameters on the linear growth rate. Moreover, the influences of the structural asymmetry on the linear growth rate have been analyzed as well.