Anomalous TEM Modes in Guiding Structures Filled With Double Negative and Double Positive Materials

In this letter, anomalous transverse electromagnetic (TEM) modes in canonical guiding structures filled with isotropic double negative and double positive materials are investigated. More specifically, it is pointed out that the propagation of a TEM mode in a particular class of dielectric loaded coaxial cables is possible if and only if the associated voltage and current waves are zero. It is also shown that this and similar unexpected behaviors are possible even in other canonical guiding structures partially filled with metamaterials