Wakefield generation in meta material-loaded waveguides

Metarnaterials (MTMs) are artificial structures made of periodic elements and are designed to obtain specific electromagnetic properties. As long as the periodicity and the size of the elements are much smaller than the wavelength of interest, an artificial structure can be assigned a permittivity and permeability, just like natural materials. Metarnaterials can be customized to have the permittivity and permeability desired for a particular application. When the permittivity and permeability are made simultaneously negative in some frequency range, the metarnaterial is called double-negative or left-handed and has some unusual properties. For example, Cherenkov radiation (CR) in a left-handed metarnaterial is backward; radiated energy propagates in the opposite direction to particle velocity. This property can be used to improve the design of particle detectors. Waveguides loaded with metarnaterials are of interest because the metarnaterials can change the dispersion relation of the waveguide significantly. Slow backward waves, for example, can be produced in a MTM-loaded waveguide without corrugations. In this paper we present theoretical studies of waveguides loaded with an anisotropic and dispersive medium(metamaterial). The dispersion relation of a MTM-loaded waveguide has several interesting frequency bands which are described. We present a universal method to simulate wakefield (CR) generation in a waveguide loaded with a dispersive and anisotropic medium. This method allows simulation of different waveguide cross sections, any transverse beam distribution, and any physical dispersion, of the medium. The method is benchmarked against simple cases, which can be theoretically calculated. Results show excellent agreement. (c) 2007 American Institute of Physics.