Losses with advanced mode matching technique
Because 3D FEM calculations are usually much slower than mode matching calculations,
Mician has introduced an advanced mode matching technique which is capable of
considering these losses by approximation. This feature has been implemented to nearly
all elements of the iris and steps library. Some elements do not support the consideration
of losses by mode matching technique yet. For those few elements one has
to select 3D-FEM on this element again.
Example for a waffle iron filter: total computation time for 500
frequency steps: 16 seconds for “ideal” and 17 seconds
for “invar” by normal sweep and 7 seconds for “ideal” and 8 seconds for “invar”
by adaptive sweep.
(Pentium IV, 2.8GHZ)
Losses by using 3D-FEM
Contrary to most of the fast Mode Matching MM/
2D FEM BCMM elements, the 3D FEM method
supports the rigorous inclusion of losses - either
dielectric or arising from finite wall conductivity -into
the calculation. Overall field calculations can be
performed at almost no additional computational
expense.
In version 6.0 of the µWave Wizard a 3D FEM solver was introduced to calculate
elements which cannot be calculated by mode-matching methods or 2D FEM.
Optionally all existing mode-matching elements can be calculated by 3D-FEM since
version 6.0 and losses arising from finite wall conductivity can be
taken into account using this 3D FEM calculation option.

