Editing Wave impedance (section)

{{Short description|Constant related to electromagnetic wave propagation in a medium}}
The '''wave impedance''' of an [[electromagnetic wave]] is the [[ratio]] of the  transverse components of the [[electric field|electric]] and [[magnetic field]]s (the transverse components being those at right angles to the direction of propagation). For a transverse-electric-magnetic ([[Transverse mode|TEM]]) [[plane wave]] traveling through a homogeneous [[medium (optics)|medium]], the wave impedance is everywhere equal to the intrinsic impedance of the medium. In particular, for a plane wave travelling through empty space, the wave impedance is equal to the [[impedance of free space]]. The symbol ''Z''  is used to represent it and it is expressed in units of [[ohm]]s. The symbol ''η'' ([[eta]]) may be used instead of ''Z'' for wave impedance to avoid confusion with [[electrical impedance]].