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Home / Examples / Electromagnetic Analysis [Hertz] / Example 13: Corrugated Waveguide
Example 13: Corrugated Waveguide
General
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The dispersion curve of a corrugated waveguide are solved. The model has uniform structure in the depth direction.
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The periodic boundary condition is applied in the 3D resonant analysis.
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Unless specified in the list below, the default conditions will be applied.
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Obtain this session's project file. (Right-click and choose 'Save link as')
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Results will vary depending on Femtet version and the PC environment.
Analysis Space
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Item |
Settings |
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Analysis Space |
3D |
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Model Unit |
mm |
Analysis Conditions
|
Item |
Settings |
|
Solver |
Electromagnetic Analysis [Hertz] |
|
Analysis Type |
Resonant Analysis |
Mesh tab, Harmonic analysis tab and Open boundary tab are set as follows.
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Tab |
Setting Item |
Settings |
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Mesh Tab |
Element Type |
2nd-order Element |
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Resonant Analysis |
Number of Modes |
5 |
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Approximated Frequency |
0 [Hz] |
|
|
Input Power |
1.0 [W] |
Model
The air domain is defined with a solid body. No boundary condition is set on the faces normal to Z axis.
The waveguide has a periodic structure. Cut out one unit to set the periodic boundary condition [PERIOD1] and [PERIOD2] to its cross sections.
The other faces are set with Electric wall PEC.
Body Attributes and Materials
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Body Number/Type |
Body Attribute Name |
Material Name |
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4/Solid |
AIR |
000_Air(*) |
* Available from the material DB
Boundary Conditions
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Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
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MW/Face |
Electric |
Magnetic Wall |
N/A |
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PERIOD1/Face |
Symmetry/Continuity |
Periodic |
N/A |
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PERIOD2/Face |
Symmetry/Continuity |
Periodic |
N/A |
|
Outer Boundary Condition |
Electric |
Electric Wall |
N/A |
Boundary Pair
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Boundary Condition Name/Topology |
Boundary Condition Name/Topology |
Boundary Condition Type |
Settings |
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PERIOD1/Face |
PERIOD2/Face |
Translational |
1 ≤ θ ≤ 359 |
Results
The phase difference of periodic boundary is varied in the range of 1 ≤ θ ≤ 359. The resonant frequencies are plotted for each angle.
The electric field at θ＝180.
This is the lowest - frequency resonant mode.
[Reference]
[1] Yu Zbu and Andreas Cangellaris, "Multigrid Finite Element Methods for Electromagnetic Field Modeling", The IEEE Press Series on Electromagnetic Wave Theory, pp. 396-397.