TEMmode
Transverse electromagnetic mode (TEM) is a class of wave in which the electric and magnetic fields are entirely transverse to the direction of propagation. In a TEM wave, there are no field components along the axis of travel; E and H fields lie in planes perpendicular to the propagation direction. TEM modes are supported by transmission lines comprising two or more conductors with a return path for current, separated by a homogeneous dielectric. Typical examples include coaxial cables and parallel-plate lines; in these structures the line supports a finite voltage between conductors without exciting longitudinal fields.
Due to the boundary conditions, TEM modes have no cutoff frequency and can, in principle, propagate from
In practice, the dominant mode in many transmission lines is TEM. In microstrip and other planar structures,
Summary: TEM mode describes a transverse-only electromagnetic field on a two-conductor transmission line with a homogeneous