# Relation between wavenumber and propagation constant

What is the exact difference between wavenumber and propagation constant in an electromagnetic wave propagating in a medium such as a transmission line, cause i am a bit confused. Does it have to do with loss in the medium?

See "Mathematical descriptions of opacity", Wikipedia.

The propagation constant has a real and an imaginary part. One of those is equal to the angular wavenumber, the other is proportional to the absorption coefficient.

Which is which (which is the real part and which is the imaginary part) depends on what definition you're using for the term "propagation constant". There is more than one definition in common use.

Here is the consensus for microwave engineering. Other fields of science may vary.


Some worked out examples for EM surface waves can be found here.

The attenuation constant is specifically the imaginary part of the wave number (ki), while the wave number in dissipative media is the real part of the wave number (kr). Let me know what you think, because I just started studying this.