Wire segment radius for a wire port in FEKO
Answers
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Hi @Sravan321
Please do not repost same question multiple times. I request to wait for experts feedback.
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Hello Sravan321,
Could anyone please help me in determining the wire segment radius for a wireport in FEKO?
I don't understand what you are asking. Do you have a model and you want to know what the wire segment radius is for the segment where the port is applied? If you have the CFX model, have a look at the wires in the details tree and identify the wire where the port is applied (you can look at the port dialog for that information) and then see if the wire as a local wire radius set. If it does, that is the value you are looking for. If not, it will be the radius defined on the mesh dialog.
Do anyone already had a .cfx file of a modeled coaxial cable of some centimeters? If so could you please attach the model for me.
I don't have one available, but it is easy to create. Are you having any specific problems with creating the model?
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Hello JIF,
Thanks for your reply.
Regarding wire segment radius:
What I mean is For example, I am modeling a dipole antenna. I created a line (which is of 0.5 mm) in between the dipole. Then I have applied a wireport to the line. When I mesh my model, I have a pop up of create mesh window. In this window I assigned a fine mesh and you can also see Wire segment radius. So now my question is how is this wire segment radius calculated and on which factors does the radius depend on. I hope you got my question now.
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I'm still not 100% sure I understand. Example A01 is an example model of a dipole. The steps to create it is roughly:
- Create the wire (your dipole)
- Add a port in the middle of the wire (no need to change the wire geometry, just add the port)
- Add a voltage source to the port
- Add requests (near / far field)
- Mesh the model
- Here you can set standard / coarse / fine / custom meshing (I think you selected fine)
- You also need to specify the default wire radius and it will be used when no local wire radius has been set. It always has to be set if the model has wire in in.
- You should set the wire radius according to the model that you want to simulate (what is the size in reality). There is a limit on the radius, since it uses a thin-line approximation, the wire segments should be at least 4 (or more) times the diameter. If this approximation starts failing, it is time to model it as a cylinder and not as a wire segment.
Does this answer your question?
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If that still does not help, maybe add your model, then I can see what you are doing.
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Hello JIF,
Thanks for your reply.
I got the answer now. I am able to define a radius but I was curoius to know the influence of the wire radius on the antenna performance. So I would like to know how the radius is calculated. But as of now I got my answer. Thanks for your suggestions again.
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Hello Jif,
I modeled a coaxial cable in FEKO. Could you please verify the model and correct me for any further changes
Thanks
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Hello
I don't see anything wrong with the model, but I suspect you want to remove the one source. At the moment you are simulating a cable with two sources at the same time. If you want to simulate a cable with a source on the one side and a sink on the other, just remove the one source (keep both ports though).
The meshing is also a bit coarse - on the advanced tab of the mesh dialog, play with the curvature refinement sliders.
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Hi JIF,
I appreciate for your help and thanks a lot for replying.
Regards,
Sravan
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Hi JIF,
I have a question regarding coaxial cable again.
I modeled a 20 cm coaxial cable with waveguide ports. But I would like to assign the characteristics to the cable like attenuation, velocity of propagation, Impedance and also shielding characteristics. But with waveguide port, I cannot assign these properties. Could you please say how the real properties of a coaxial cable can be assigned in feko.
Thanks,
Regards,
Sra
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Hello Sra,
The properties that you describe can't be 'set on a cable' if you model the cable by creating the geometry, because the properties that you want to set are the result of the cable geometry and media being used. In the same way that the ratio of the center conductor to outer conductor (on the inside) and the dielectric material inside the coax determines the impedance of the transmission line, the medium determines the velocity of propagation and the losses in the model will determine the attenuation. Thus, it is not possible to set these and model the physical dimensions and media used in the coaxial line. Makes sense?
If you simply want to model a transmission line in a larger model, FEKO also supports cable modelling where a list of commonly used cables can be selected. You could also model is simply as a non-radiating transmission line and then you define the impedance, attenuation and propagation velocity. There are examples in the example guide for both cables and non-radiating transmission lines.
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