his case explains how to calculate far-field, radiation pattern, current density, charge density and near field of a corrugated horn.
Step 1: Create a new MOM Project.
Open 'New Fasant' and select 'File --> New' option.
Figure: New Project panel
Select MOM option on the previous figure and start to configure the project.
Step 2: Change the scale to millimeters
Figure: Scale settings
Step 3: Create the geometry of the corrugated horn
Execute the function “corrugated_horn(fmin,fmax)”, which can be downloaded here.
To execute the function, click on Tools - Calculator and write the call to the function.
Figure: Calculator panel
The parameters to set are:
fmin: is the lowest operating frequency (GHz)
fmax: is the highest operating frequency (GHz)
The script file, called “script_corrugated_horn.nfs”, will be automatically generated in the mydatafiles folder in the newFASANT directory.
The next step is to execute the generated script file. For that, click on Tools – Script - Load and open the script “script_corrugated_horn.nfs”.
Horn geometry has been generated.
Step 4: Set Simulation Parameters
Select 'Simulation --> Parameters' option on the menu bar and the following panel appears. Set the parameters as the next figure shows and save it.
Figure: Simulation Parameters panel
Step 5: Set the source parameters.
Select 'Source --> Dipole --> Dipole Antenna' option and set the parameters as show the next figure. Then save the parameters and the dipole appears.
Figure: Dipole Antenna panel
Select 2 electric dipoles and click on “Position”.
Figure: Electric Dipole 1 Settings
Figure: Electric Dipole 2 Settings
Step 6: Set the solver parameters.
Click on Solver --> Parameters option on the menu bar. Verify that all the parameters are defined by default, as shown in next figure. Click on Save button before going to next step.
Figure: Solver panel
Select ‘Advanced Options’ and activate Preconditioner as shown.
Figure: Preconditioner panel
Step 7: Meshing the geometry model.
Select 'Meshing --> Parameters' to open the meshing configuration panel and then set the parameters as show the next figure. In order to obtain the shortest possible time for meshing, it is recommended to run the process of meshing with the number of physical processors available to the machine.
Figure: Meshing panel
The user can choose between:
- octaves: an automatic frequency range per octave is performed, that depends on the Initial and Final frequency. The user can choose 1 frequency by an octave or several frequencies by an octave. The more frequencies per octave, the greater the precision
- all frequencies: a meshing by each frequency is built, so it is the more accurate option. This option will only be chosen when the user needs a very accurate mesh.
Step 8: Execute the simulation.
Select 'Calculate --> Execute' option to open simulation parameters. Then select the number of processors as the next figure show. In order to obtain the shortest possible time for calculating the results, it is recommended to run the process with the number of physical processors available to the machine.
Figure: Execute panel
Then click on 'Execute' button to starting the simulation.
Step 9: Show Results.
To get more information about the graphics panel advanced options (clicking on right button of the mouse over the panel) see Annex 1: Graphics Advanced Options on GUI User Guide.
Select 'Show Results --> Far Field --> View Cuts' option to show the cuts of the observation directions options.
Figure: Far Field cuts - Linear Amplitude
Selecting other values for the component, step, frequency or cut parameters and clicking on 'Add Series' button a new cut will be added to the selected parameters.
On 'Show Results --> Far Field' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
On 'Show Results --> Radiation Pattern' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
Select 'Show Results --> Radiation Pattern --> View 3D Pattern' option to show the cuts of the radiation pattern options.
Figure: Radiation Pattern 3D
Changing values for step, frequency, component or filtering parameters the visualization for the new parameters will be shown.
Select 'Show Results --> View Currents' option to show the current density.
Figure: Current Density
Changing values for step, frequency, magnitude, component or filtering parameters the visualization for the new parameters will be shown.
Select 'Show Results --> View Charges' option to show the charge density.
Figure: Charge Density
Changing values for step, frequency, magnitude or filtering parameters the visualization for the new parameters will be shown.
On 'Show Results --> Far Field' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
This case explains how to calculate far-field, radiation pattern, current density, charge density and near field of a corrugated horn with 22 dB gain at 10 GHz.
Step 1: Create a new MOM Project.
Open 'New Fasant' and select 'File --> New' option.
Figure: New Project panel
Select MOM option on the previous figure and start to configure the project.
Step 2: Change the scale to millimeters
Figure: Scale settings
Step 3: Create the geometry of the corrugated horn
Execute the function “corrugated_horn_gain(fmin,fmax,alfa,D)”, which can be downloaded here.
To execute the function, click on Tools - Calculator and write the call to the function.
Figure: Calculator panel
The parameters to set are:
fmin: is the lowest operating frequency (GHz)
fmax: is the highest operating frequency (GHz)
alfa: is the flare angle (obtained from the following graph)
D: is the aperture diameter (obtained from the following graph)
In this case, we will simulate at 10 GHz, so the maximum and minimum frequency are 10 GHz.
To choose the flare angle and the aperture diameter, observe the next graph.
For a gain of 20 dB a flare angle of 15 ° and a diameter of 5.5 times, λc is chosen. So:
Alpha = 15
D = 5.5
The script file, called “script_corrugated_horn_gain.nfs”, will be automatically generated in the mydatafiles folder in the newFASANT directory.
The next step is to execute the generated script file. For that, click on Tools – Script - Load and open the script "script_corrugated_horn_gain.nfs".
Horn geometry has been generated.
Step 4: Set Simulation Parameters
Select 'Simulation --> Parameters' option on the menu bar and the following panel appears. Set the parameters as the next figure shows and save it.
Figure: Simulation Parameters panel
Step 5: Set the source parameters.
Select 'Source --> Dipole --> Dipole Antenna' option and set the parameters as show the next figure. Then save the parameters and the dipole appears.
Figure: Dipole Antenna panel
Select 2 electric dipoles and click on “Position”.
Figure: Electric Dipole 1 Settings
Figure: Electric Dipole 2 Settings
Step 6: Set the solver parameters.
Click on Solver --> Parameters option on the menu bar. Verify that all the parameters are defined by default, as shown in next figure. Click on Save button before going to next step.
Figure: Solver panel
Select ‘Advanced Options’ and activate Preconditioner as shown.
Figure: Preconditioner panel
Step 7: Meshing the geometry model.
Select 'Meshing --> Parameters' to open the meshing configuration panel and then set the parameters as show the next figure. In order to obtain the shortest possible time for meshing, it is recommended to run the process of meshing with the number of physical processors available to the machine.
Figure: Meshing panel
Step 8: Execute the simulation.
Select 'Calculate --> Execute' option to open simulation parameters. Then select the number of processors as the next figure show. In order to obtain the shortest possible time for calculating the results, it is recommended to run the process with the number of physical processors available to the machine.
Figure: Execute panel
Then click on 'Execute' button to starting the simulation.
Step 9: Show Results.
To get more information about the graphics panel advanced options (clicking on right button of the mouse over the panel) see Annex 1: Graphics Advanced Options on GUI User Guide.
Select 'Show Results --> Far Field --> View Cuts' option to show the cuts of the observation directions options.
Figure: Far Field cuts - Linear Amplitude
Figure: Far Field cuts - Polar Amplitude
Selecting other values for the component, step, frequency or cut parameters and clicking on 'Add Series' button a new cut will be added to the selected parameters.
On 'Show Results --> Far Field' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
Select 'Show Results --> Radiation Pattern --> View Cuts' option to show the cuts of the radiation pattern options.
Figure: Radiation Pattern cuts
Selecting other values for the component, step, frequency or cut parameters and clicking on 'Add Series' button a new cut will be added to the selected parameters.
On 'Show Results --> Radiation Pattern' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
Select 'Show Results --> Radiation Pattern --> View 3D Pattern' option to show the cuts of the radiation pattern options.
Figure: Radiation Pattern 3D
Changing values for step, frequency, component or filtering parameters the visualization for the new parameters will be shown.
Select 'Show Results --> View Currents' option to show the current density.
Figure: Current Density
Changing values for step, frequency, magnitude, component or filtering parameters the visualization for the new parameters will be shown.
Select 'Show Results --> View Charges' option to show the charge density.
Figure: Charge Density
Changing values for step, frequency, magnitude or filtering parameters the visualization for the new parameters will be shown.
On 'Show Results --> Far Field' menu, other results are present such as 'View Cuts by Step' and 'View Cuts by Frequency' and this option display the values for one selected point for each step or frequency.
This case explains how to add a new profile of the corrugated horn.
Step 1: Create a new MOM Project.
Open 'New Fasant' and select 'File --> New' option.
Figure: New Project panel
Select 'MOM' option on the previous figure and start to configure the project.
Step 2: Open the function
Select 'Tools --> User Functions' option on the menu bar and open the function "corrugated_horn.java" or "corrugated_horn_gain.java".
Figure: User Functions panel
Look for the 'try' exception and the IF ... ELSE IF statement with the "profile_index" parameter in the section 'Corrugated surface profile formulations':
Figure: Exception 'try' and if...else statement
The last 2 profiles (profile_index==8 and profile_index==9) are reserved for the user profile formulation. User profile 1 and User profile 2.
Step 3: Introduce the profile formulation
In this example, we will establish a linear profile in user profile 1 (profile_index==8).
The linear profile has the following formulation:
Figure: Linear profile formulation
where:
ai: input radius
ao: output radius
L: length
z: in the variable parameter. It is necessary to enter it as i*p
We look for the 'User profile1' within the function:
Figure: User profile 1 and 2
And write our function, which in this case is the linear profile:
az[i]=ai+(ao-ai)*(i*p/L);
Notes that 'z' has been changed to 'i*p'
Step 4: Select the user profile 1
To activate the profile entered, we have to select it within 'Profile Type Parameters' at the beginning of the function. In this case we select the profile index number 8 (profile_index = 8;)
Figure: Select the profile index
Step 5: Save the function
Finally, save the changes. Save it clicking on 'SAVE' or 'SAVE ALL' button.
Figure: Save the function
Step 6: Show Results
The corrugated horn with linear profile has been generated.
To simulate it, follow examples 15.12.1 or 15.12.2, depending on the user function where the new profile has been established.
This case explains how to calculate S-parameters of a corrugated horn.
Step 1: Create a new MOM Project.
Open 'New Fasant' and select 'File --> New' option.
Figure: New Project panel
Select MOM option on the previous figure and start to configure the project.
Step 2: Change the scale to millimeters
Figure: Scale settings
Step 3: Create the geometry of the corrugated horn
Execute the function “corrugated_horn(fmin,fmax)”, which can be downloaded here.
To execute the function, click on Tools - Calculator and write the call to the function.
Figure: Calculator panel
The parameters to set are:
fmin: is the lowest operating frequency (GHz)
fmax: is the highest operating frequency (GHz)
The script file, called “script_corrugated_horn.nfs”, will be automatically generated in the mydatafiles folder in the newFASANT directory.
The next step is to execute the generated script file. For that, click on Tools – Script - Load and open the script “script_corrugated_horn.nfs”.
Horn geometry has been generated.
Step 4: Set Simulation Parameters
Select 'Simulation --> Parameters' option on the menu bar and the following panel appears. Set a Frequency Sweep and the S-Parameters Simulation type as shown in the figure below. Remember clicking on Save button to confirm the changes.
Step 5: Set the source parameters.
Note: this option requires that the geometry must be only one object (use the group command if it is not) and the waveguide cap needs to be removed
To add a waveguide port, select the object and click on 'Source' --> 'Waveguides' --> 'Add Waveguides Port' menu to open the panel.
And follow the steps describes on Add Waveguide Port
Step 6: Set the solver parameters.
Click on Solver --> Parameters option on the menu bar. Verify that all the parameters are defined by default, as shown in next figure. Click on Save button before going to next step.
Figure: Solver panel
Select ‘Advanced Options’ and activate Preconditioner as shown.
Figure: Preconditioner panel
Step 7: Meshing the geometry model.
Select 'Meshing --> Parameters' to open the meshing configuration panel and then set the parameters as show the next figure. In order to obtain the shortest possible time for meshing, it is recommended to run the process of meshing with the number of physical processors available to the machine.
Figure: Meshing panel
The user can choose between:
- octaves: an automatic frequency range per octave is performed, that depends on the Initial and Final frequency. The user can choose 1 frequency by an octave or several frequencies by an octave. The more frequencies per octave, the greater the precision
- all frequencies: a meshing by each frequency is built, so it is the more accurate option. This option will only be chosen when the user needs a very accurate mesh.
Step 8: Execute the simulation.
Select 'Calculate --> Execute' option to open simulation parameters. Then select the number of processors as the next figure show. In order to obtain the shortest possible time for calculating the results, it is recommended to run the process with the number of physical processors available to the machine.
Figure: Execute panel
Then click on 'Execute' button to starting the simulation.
Step 9: Show Results.
To get more information about the graphics panel advanced options (clicking on right button of the mouse over the panel) see Annex 1: Graphics Advanced Options on GUI User Guide.
When the simulation process has finished, the S-Parameters are enabled within the results menu. Click on Show Results menu and S-Parameters option to visualize these parameters. The panel with the available options to visualize the S-Parameters is open on the right side.
Figure: S-Parameters parameters
Select the S-Matrix Representation and the option db, Phase in Representation section. Then, select the column to represent in the Results table and then click on Chart button to add them to plot them.
Figure: S11parameters plot
Figure: S11 parameters table