This International Standard is applicable to the sweep frequency method used for the measurement of return loss on waveguide and waveguide assemblies.
Return loss is defined as
ar = 20 log (ui/ur) dB
where
ui is the magnitude of the incident wave;
ur is the magnitude of the reflected wave.
Return loss is related to the reflection coefficient, r, by:
r=(ur/ui) r=10
Fundamentally the method involves measuring the amplitude of the reflected wave at the waveguide under test (WUT) input by means of a ref lectometer device.
The reflected wave can be compared with the total reflected wave under short-circuit conditions, attenuated by a calibrated attenuator, or it can be compared with the incident wave by means of reflectometer.
BS EN 61580-6:1997 history
1997BS EN 61580-6:1997 Methods of measurement for waveguides. Return loss on waveguide and waveguide assemblies