"Meindert Sprang" wrote

"Jack Painter" wrote

Hi Gary, the difference that is relevant, I believe, is a waveguide for
microwave broadcast through the inside space of the guide, and there is
minmal current intentionally allowed on the waveguide.

Wrong Jack. Electromagnetic waves in a waveguide are only possible when
voltages and currents are present. The maximum voltage is between the two
larger sides while currents flow from one side to the other. The entire
field is contained inside the waveguide and therefore the inside surface
must have a low resistance and is silver plated to achieve this. You can
read this in any textbook on microwave transmission.

Hi Meindert, how is that skin effect when, as you said, the currents must
flow from one side to the other? Skin effect would hold currents _on_ the
surface, slow them down, and reduce the reflection that is required for
propagation through the guide.

Why do you think a microwave reflects on the wall of the waveguide?
Because
current flows on the inside wall, which has to have the lowest resistance
possible. It is all skin effect what makes a waveguide tick!

That sounds like a contradiction (current flows from one side to the other,
and current flows on the inside wall, [the latter of which would be skin
effect] ), can you explain please?

Thanks,

Jack