Tip:
Highlight text to annotate it
X
This quick example will show you the process of automated design and analysis of a corrugated
horn antenna designed to work at a particular gain.
The design of antennas can sometimes be a hard task.
Although newFASANT already provides many predesigned antennas, sometimes you just have to do all
the modeling by yourself, either using our powerful geometric toolset, or a different
software tool.
Recently at newFASANT, we tried to address the following question: what if instead of
spending a lot of time doing all the modelling, we could have the computer do the modelling
in behalf of us.
newFASANT integrates an user function system that you can use to define advanced functions
that you can use during the design of projects or as a general macro tool.
We can use this software to generate the script that we can later execute in order to define
these geometries.
That's why we made this user function, that you can use to build corrugated horn antennas.
There is a link in the description to this user function that you can get for free from
our website.
Download the user function, place it in the appropiate directory, and you are ready to
go.
Let's take a look at the function code.
Some parameters, must be set every time the function is invoked, because they will usually
change.
These are fmin and fmax, the initial and final frequency for the antenna; alpha, the flare
angle; and D, the aperture diameter.
There are also other parameters that you may not usually want to change a lot, and therefore,
they are set as local variables.
They have different values that you can keep, unless there is something particular you want
to change.
For instance, you could change the length of the waveguide, or the sloth pitch.
Maybe, the most interesting variable that you can play with, is the profile index.
If you take a look at the user function information, you will find there are different profiles
to use with this antenna, each one associated with a different kind of antenna.
You can set the profile to linear, sinusoid, tangential, and so on.
In this case, the profile will be set to 1, linear, for example.
And finally, you will have to set the file name where you want the generated script to
be placed in.
So, set the script variable to the name of the file that you want to generate.
In this case, I'm going to use corrugated_with_gain.
Then, how to create this script?
Simply open the calculator.
The calculator is an interactive evaluator that lets you run Java code.
You can use this calculator to execute any Java code, including the user functions available
in the system.
So, if I wanted to generate a horn that specifically works in the 10 GHz band, with a flare angle
of 15 degrees and an aperture diameter of 5.5 meters, I could execute corrugated_horn_gain()
and set as parameters 10 and 10 -because that is the frequency; 15 -which is the angle in
degrees, and 5.5 -which is the diameter in meters for this antenna.
Press ENTER to run the script.
If we don't see any errors, this means that the script has been correctly generated.
In order to load the script, simply go to Tools | Script | Load, and select the script
file.
Please, note that this is not a geometric file.
This is just a script file, containing a list of commands.
If you load the script, all the commands in this file will be processed by the console,
and the geometry will be generated.
So, select the file and press Open.
Here is the final design for our antenna.
We could use this antenna in a design, or we could export this geometry for a later
use.
What if I wanted to do a simulation with this horn in order to analyze all the properties?
Let's design a simulation with this antenna.
First, let's set the frequency.
I said I wanted this antenna to operate with a frequency of 10 GHz, so the first thing
that I'm going to change is the frequency, by going to Simulation properties, and setting
a frequency of 10 GHz.
Now, let's add the dipole, on this side of the antenna.
Go to Source | Dipole | Dipole Antenna, and add a dipole at the position -90 mm in the
Z axis, this side actually.
This dipole is going to have 2 electric dipoles.
So set the number of electric dipoles to 2.
And let's go to Position in order to set the properties.
Both dipoles will have a theta angle of 90 degrees.
However, the second one is also going to have a phi angle of 90 degrees, and a phase of
90 degrees as well.
Press OK to save the changes, and then press Save to add the dipole.
Finally, in order to speed up the process, I'm going to change a few solver settings.
First, the architecture is going to change to OpenMP.
I'm not using a cluster computer, so it will be faster here if I use OpenMP instead of
MPI.
Plus, by clicking on Advanced Options, I can enable the preconditioner.
The preconditioner will add a few preprocessing steps to the project, in order to make the
process go faster.
Press Save in both windows in order to save the changes, and we are ready to go.
Our last steps are the Meshing and the Calculation.
To mesh the project, simply go to Meshing | Create Mesh.
Simply set the frequency to the frequency that is set in the project, and set the number
of processors to the number of processors that you have in your system.
Then, press Mesh to start the process.
After the meshing is done, we can close the process Log window.
Then, we can go to Calculate | Execute in order to do the actual calculation.
Set the number of processors to the number of processors that you have in your system,
and press Execute to start the calculation.
After the simulation has been completed, the Show results menu will be enabled.
This menu will display to you multiple properties about the antenna that you just simulated.
For the complete information on this menu, I'm asking you to take a look at the MOM User
Guide, where you can find more comprehensive explanation on every option.
However, I want to show you some things that you can do with MOM.
You can view the Far Field cuts for the observation directions.
You can also view the 3D Radiation Pattern for the antenna.
It is also possible to view the current density diagram, and the charges density diagram.
Both of them will display the value for the currents and the changes through the antenna
surface.
If you have any further question, you can ask us in the comments for this video, or
you can get in touch with us, through other platforms, such as the forums or direct e-mail.
Thanks a lot for watching, and have a nice day.