Regime di propagazione unimodale e proprietà radiative in guide d'onda NRD metamateriali

Nonradiative dielectric (NRD) waveguides employing time-dispersive isotropic metamaterial slabs sandwiched between metal plates are studied. Dispersion properties of bound (surface) and leaky modes are considered for both double-negative and single-negative layers. As concerns the bound modes, ranges of unimodal backward propagation are achieved for the operating low-loss LSM01 mode by means of epsilon-negative media. Parametric analyses are performed to determine suitable frequency ranges of unimodal propagation and the attainable frequency bandwidths. Complex proper leaky modes supported by double-negative NRD guides are also illustrated, which show physical ranges of radiation into the first higher-order TE1 mode of the background parallel-plate waveguide.