metamaterial

In this paper we present overview of devices using a dielectric as a slow-wave structure. There are increased focus on consideration of dielectric Cherenkov maser (DCM) and resistive-wall amplifier (RWA). This type of devices may be advance in THz range. The principle of the DCM operation is described by two-dimensional planar model with the indication of main advantages of this device.

Resistive wall amplifier is a vacuum microwave device, which has not been spread, but attracts attention again. Main features – no need to slow-wave structure and almost complete lack of feedback between output and input. The amplification occurs due to the phase shift between the electron beam and field variables that arise due to the presence of absorbing walls.

The review of works on studying artificial media with negative refractive index and  their unique application is given. We make a point of negative refraction and lens effects in plan-parallel  layers of such metamaterials. The properties and stability conditions of waveguide modes in  layered structures and open cavities are considered in terms of the effective diffraction and  dispersion lengths.