I am working on dielectric-lined circular waveguides and I am searching
for a reference on the orthogonality of modes. The only thing that I
found is in the link below (at the bottom of the message)
but I am looking for something with more details.

Assume that we have a uniform cylindrical waveguide with N concentric
dielectric layers [my case of interest is when N=2, and we have the
waveguide with a thin inner dielectric layer (second layer N=2) and the
rest is vacum (air- N=1- first "layer")].
I need an orthogonality relation that applies between any two modes.
The fact is that I already have found an orthogonality relation (see
the link below) but I need a more detailed analysis.

http://www.bnl.gov/ATF/experiments/D...y_of_Wakes.pdf

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