In this paper we investigate the conditions for energy tunneling through narrow channel obtained by reducing the height of rectangular waveguide.Tunneling of the energy occurs at the frequency for which the effective RCA Adapters dielectric permittivity of the channel becomes equal to zero, so it can be treated as an ENZ (epsilon-near-zero) metamaterial.We investigated how geometry of the channel and dielectric permittivity affect the transmission coefficient and field density in the channel.Adding slots Miscellaneous Skate in the channel, which are placed orthogonally to the wave propagation, we designed a small antenna with directivity of 5.
44 dBi at the frequency of 3 GHz.