| the complex ratio of a sinusoidal field quantity, such as a reflected current or reflected wave component, to the corresponding field quantity of the incident current or incident wave at a point near the surface separating two propagation media, near a port of an electrical network or near a discontinuity in a transmission line
NOTE 1 – When the field quantity is a component of a plane electromagnetic wave, the sign of the reflection factor is different for an electric field component and the corresponding magnetic field component.
NOTE 2 – When the field quantity refers to a port of an electrical network, or to a discontinuity in a transmission line, a voltage reflection factor can be defined with a sign opposite to that of the current reflection factor.
NOTE 3 – When impedances can be defined, the complex current reflection factor r equals:
where Z is the characteristic impedance of the transmission line ahead of the discontinuity or the impedance of the source and Z′ is the impedance after the discontinuity or the load impedance seen from the junction between the source and the load.
NOTE 4 – The reflection factor depends in the case of waveguides on the electromagnetic mode considered.