RF MODULE

3 In the New Function dialog box, enter the Function name nu_brass.
4 Click the Interpolation button, then select File from the Use data from list.
5 Click the Browse button, locate and select the file mw_filter_freqs_brass.txt
that you just generated, and finally click Open. Alternatively, you can use the file with
this name located in the models Model Library folder (models/RF_Module/
RF_and_Microwave_Engineering under the COMSOL installation directory).
6 Optionally, select the Store data in file check box. This makes the model MPH-file
self contained, but it has the potential drawback that changes in the source data file
are not taken into account.
7 Click OK to close the New Function dialog box.
8 Repeat the Steps 2 through 7 to define the interpolation function nu_steel using
the data file mw_filter_freqs_steel.txt.
9 Click OK to close the Functions dialog box.
To make the interpolation functions available for postprocessing, create two global
expression.
1 From the Options menu, point to Expressions and then choose Global Expressions.
2 In the Global Expressions dialog box, define the following expressions:
NAME EXPRESSION DESCRIPTION
nu_brass nu_brass(T1) Frequency, brass
nu_steel nu_steel(T1) Frequency, steel
3 Click OK.
Updating the Model
Next, use the parametric solver to generate a set of “dummy” solutions for the same
parameter and range as the parametric sweeps you just performed.
1 Click the Solver Parameters button on the Main toolbar.
2 Change the Solver to Parametric.
3 In the Parameter names edit field type T1, and in the Parameter values edit field type
range(273.15,10,373.15).
4 Click OK to close the Solver Parameters dialog box.
5 Click the Solver Manager button on the Main toolbar.
6 On the Solve For page, select only the Shell (smsh) variables.
7 On the Sequence page, clear the Solve using a solver sequence check box.
108 | CHAPTER 3: RF AND MICROWAVE MODELS