Terminology
Introduction to microwaves

An electromagnetic wave is characterized by :

• the description at any instant of the amplitude and orientation of the electric E and magnetic H fields constituting it. The ratio of the components transverse to the direction of propagation E_T/H_T is the transverse wave impedance Z_T. The orientation of the electric field defines polarization;

• its frequency f (in Hz or multiples thereof) ;

• its propagation speed v. In a vacuum, this is equal to that of light, i.e. c = 2.997.10⁸ m.s^-1; in any medium v = c/n where n is the index of the medium, generally dependent on frequency. The wavelength is λ (in m) = v/f ;

• its direction, defined by the director cosines of the wave vector, vector k of modulus equal to 2π/λ, locally perpendicular to the wave surface ;

• the...