Multiple Monopole Antenna Simulation
Altair EmployeeAnswers
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Hello mustaphos,
Just create a ground plane and add multiple monopole antennas (port and excitation for each antenna) and you have multiple monopole antennas with a single ground. The ground can be finite or infinite (planar multi-layer substrate). Or did I misunderstand what you are trying to ask?
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Altair Forum User said:
Hello mustaphos,
Just create a ground plane and add multiple monopole antennas (port and excitation for each antenna) and you have multiple monopole antennas with a single ground. The ground can be finite or infinite (planar multi-layer substrate). Or did I misunderstand what you are trying to ask?
You understand correctly.
But my antennas will be placed on a tower.
When i add edge port to an antenna i get this error:
'Error 19020: Geometry port: Port1 - The specified faces do not have any common edges where the port can be applied'
my ground plane will be placed to the ground and my antennas will be placed 7m above this plane.
Is there a way to connect the ground plane to the antennas in FEKO?
Also i am trying to create a ground plane but i am unable to create it like 5meter x 5meter square.
In the ground plane section in FEKO there is no option for that.
Regards.
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Everything that you want to do should be possible. You would probably want to model the ground (earth) using a real ground (not PEC). You can take a look at 'Yagi-Uda Antenna Above a Real Ground' in the Example Guide as an example to add a real ground. If you have a PEC ground, then you can model that as well. Or you can model it with a finite metal ground (much more expensive in terms of simulation resources).
The features in FEKO are designed around what is possible in reality. It thus helps to think about what happens in reality when creating the model. If you have a monopole antenna, it will surely assume to be attached to a ground plane, even if that ground plane is the pole that it is mounted on. If that is the case, add your excitation between the antenna and the ground structure. You can also create a more realistic model by simply feeding the antenna with a transmission line - you would then be modelling the cable feeding the antenna.
If you need more help, I suggest that you add the model or at least some pictures.
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Altair Forum User said:
Everything that you want to do should be possible. You would probably want to model the ground (earth) using a real ground (not PEC). You can take a look at 'Yagi-Uda Antenna Above a Real Ground' in the Example Guide as an example to add a real ground. If you have a PEC ground, then you can model that as well. Or you can model it with a finite metal ground (much more expensive in terms of simulation resources).
The features in FEKO are designed around what is possible in reality. It thus helps to think about what happens in reality when creating the model. If you have a monopole antenna, it will surely assume to be attached to a ground plane, even if that ground plane is the pole that it is mounted on. If that is the case, add your excitation between the antenna and the ground structure. You can also create a more realistic model by simply feeding the antenna with a transmission line - you would then be modelling the cable feeding the antenna.
If you need more help, I suggest that you add the model or at least some pictures.
Hi JIF.
Thanks for quick answer.
You can see in the image that i am simulating my multiple antennas with individual ground plane which i think is a wrong approach to this particular problem.
I had to somewhat connect all of them in a single ground plane placed on (0,0,0).
I made monopole arms as cylinder so i can add all of them individual edge ports.
For positive faces of edge ports i can add monopole arm edges but i can not add negative face to ground plane because i get the error.
'Error 19020: Geometry port: Port1 - The specified faces do not have any common edges where the port can be applied'
But i think i had to connect somehow to a single ground plane (like shielded cable between ground plane to monopole arms).
How can i do it?
Thanks...
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Anyone?
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Sorry mustaphos, I have been trying to answer you all day - other things keeping me busy (also traveling).
I think we need to step back and define what you are trying to model. Are you trying to model an existing system or are you designing a system? If you are designing a system, I think you should reconsider your antenna choice. A monopole is not the antenna that you should use here (probably). For a monopole, you are going to have to add a ground plane in some form or another. Anything other than a perfect PEC ground plane is an approximation to what you want. Options include the ground planes that you have added or an approximation to a ground plane using wires or something similar. You could also use your structure (mast) as a ground plane, but I would not recommend this - it is going to severely affect your antenna performance as you modify the structure and connection to the structure and is not a practical solution.
If you are simply trying to create a model of something that already exists, I would take a closer look at the antenna. The omni antennas are probably not simple monopoles, but probably a collinear antenna array.
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Altair Forum User said:
Sorry mustaphos, I have been trying to answer you all day - other things keeping me busy (also traveling).
I think we need to step back and define what you are trying to model. Are you trying to model an existing system or are you designing a system? If you are designing a system, I think you should reconsider your antenna choice. A monopole is not the antenna that you should use here (probably). For a monopole, you are going to have to add a ground plane in some form or another. Anything other than a perfect PEC ground plane is an approximation to what you want. Options include the ground planes that you have added or an approximation to a ground plane using wires or something similar. You could also use your structure (mast) as a ground plane, but I would not recommend this - it is going to severely affect your antenna performance as you modify the structure and connection to the structure and is not a practical solution.
If you are simply trying to create a model of something that already exists, I would take a closer look at the antenna. The omni antennas are probably not simple monopoles, but probably a collinear antenna array.
Hi again JIF.
I am trying to model an existing system so i can not change the antennas or antenna tower.
I had to simulate as it is but i could not be able to do that.
I had to find a way to use a single ground plane for multiple antennas.
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If you are trying to model an existing system, I would suggest that you take a closer look at the antennas on the tower. I'm pretty sure that they are not monopols (even if they look like monopoles). They are most likely colinear antennas. The single ground is not the problem - you can just add the ground under the tower to take the effect of the ground / earth into account.
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