What does mode matching mean?

Hallo,
can somebody please tell me what is meant with the term "mode matching".
To me, it looks like a Method of Moments method.

Thanks

Hi electr0 !
Basically "mode matching" is a technique of analytically "sewing" modes at waveguide discontinuities.
It is not a numeric method. You can read more here:
http://www.maasdesign.co.uk/modematch.html

Hi,

I'm not a mode matching expert but I believe it is actually semi numerically.

Inside a waveguide structure you have an infinite (but discrete) number of specific modes (field patterns) which can exist. If you now have some "real" fields these fields can be expressed in terms of a sum of these modes. In order to get the correct representation, each mode is weighted by a certain factor.

Now, if you have a discontinuity the fields right at this points can be expressed form both sides. The sum of the Eigenmode* weighting factors from one side of the discontinuity have to be equal to the sum of the Eigenmodes * weighting factors from the other side.

By knowing this, you can figure out the weighting factors for both sides of the discontinuity. If you have those, you know how the fields inside the "homogeneous" parts of the waveguide look like. Some parts of this (I guess the calculation of the weighting factor) are done numerically, some other parts (Eigenmode calculation) can be done analytically..

Mode matching can be extremely fast (much faster then any other 3D EM method) but the drawback is, that it only works for a limit set of structures.

If there is any "mode matching expert" around please correct me If I'm mistaken..


F.

Ok.

Thanks RFSimulator, navuho.