# oussama1

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1. ## Extending the Transmission line modelling in FEKO

Dear All, i think the transmission line modelling of shielded cables can be improved in your FEKO software by using the generalized formula of the transfer impedance and admittance that i have proposed in the following publication. https://ieeexplore.ieee.org/document/9106764 the proposed formula can be applied for any multi-shielded cables.
2. ## the wire is not electrically connected to a metalic face

this is a cable model and i want to obtain its s-parameters by obtaining the touchstone file. in the real cable. the bare above wire should be electrically connected to the shield. however, in the wire model the wire is not connected to the shield even if i union the shield with the wire. please, what i should do to make the wire electrically connected to the shield? also can you explain your expression " " by providing an image
3. ## the wire is not electrically connected to a metalic face

thank you so much for your reply. i have attached a simpler model (parallel not twisted). my purpose is to make the wire electrically connected to the shield, but this cannot be occurred since the wire surface defined by its radii is purely analytical. you said that if i draw a line going intro a cylinder and union, how ? did you mean the wire should be exactly on the shield surface? (i have tested that, but feko had ignored this wire after meshing). i really i didn't understand your last point. please, can you show me a screen shot. thank you in advance. wire_not_connected.cfx
4. ## the wire is not electrically connected to a metalic face

i constructed the cable shown in the attached image. the bare above wire should be electrically connected to the metallic shield. however, feko does not consider the wire and the shield surface connect even i have union them together. what do you suggest ? does there is a way to make the wire with a given radius connected to the shield surface taking in consideration the wire radius. (it means the shield surface is far from the wire center by rw (wire radius) as shown in the image).

6. ## my simulation is slow

the simplified model in the attachment. i would like to calculate the s parameters of this cable. please can you help me, i need to know if the s-parameters extraction is correct or not. i have reduced the meshing and the simulation was faster, however it was wrong as compared to the measurement data. any suggestions about the s-parameters extraction? any help would be appreciated. thank you in advance. model22.cfx
7. ## my simulation is slow

thank you so much for you answer, please can you guide me how to use a different solver and which solver is appropriate.
8. ## my simulation is slow

please check the attached image. when i started the simulation, the simulation is remained at that process of a long time. what is the problem?
9. ## simulating triaxial cable with waveguide port error!!

thank you so much for your help
10. ## How can we add an aperture into curvature surface?

thank you for your help @Derek Campbell
11. ## How can we add an aperture into curvature surface?

the problem solved. i have built the model in feko. However, the process become so slow during the projection of 3000 apertures over the cylindrical surface. my model is the attached image. simple braided shield model in feko
12. ## what is Absorbing Waveguide Terminations?

Since no one has answered my question i would like to answer it by my self. waveguide ports without sources are considered to be absorbing i.e. are connected to their characteristic impedance. i have validated that by extracting the S-parameters and i found s11 is equal to zero given port two connected to waveguide port without source.
13. ## simulating triaxial cable with waveguide port error!!

I want to simulate triaxial cable as shown in the attached image. i have use waveguide port, however, error is occurred, please can you tell me where is the mistake in my model. the model is also attached. thank you in advance. output file results triaxial cable.cfx
14. ## what is Absorbing Waveguide Terminations?

Waveguide ports without sources are considered to be absorbing waveguide terminations in FEKO. i m wondering that if it is possible to consider those terminations as matched terminals ? simply : absorbing waveguide terminations = matched terminations ???? let's suppose a coaxial cable in which waveguide ports are considered. port 1 is connected to a waveguide source, where the port 2 is not connected. is it possible to say that the port 2 is connected to the characteristic impedance of the coaxial cable Z0=sqrt(L/C) ? where L and C are the p.u.l parameters of the coaxial cable Coaxial cable with waveguide ports
15. ## How can we add an aperture into curvature surface?

thank you so much @Derek Campbell
16. ## How can we add an aperture into curvature surface?

I would like to build something like that
17. ## How can we add an aperture into curvature surface?

I want to add apertures (holes) over curvature surface (cylindrical for example). How can i do this ? my purpose is to model braided-shielded cable. thank you in advance
18. ## The terminals of shielded cable

thank you so much for your help, you are a great helpful person
19. ## The terminals of shielded cable

please check the attachment to see my model coxial_cable_testing_real_shielding_6_perfect_conductor_cylindrical.cfx
20. ## The terminals of shielded cable

thank you so much, if i use cylinder wire, how can we add a load to it? should i use small segment wire to add a load ? or there is another way ? also, what is stray inductance, how can i add it and how i should connected to the grounding wires? thank you in advance.
21. ## The terminals of shielded cable

thank you so much for your help. However, how can we mesh the cylinder into triangles with the edge lengths the same as the spacing between the inner and outer conductor ? what about the outer conductor connection to the ground? should i use wire approximation or cylindrical ?
22. ## The terminals of shielded cable

what is the best terminal geometry of a coaxial cable so that to get high accuracy results ? please see the following figures case 1 : case 2 : However, both results does not agree with TLM solution performed by FEKO. why? is the terminal connection geometry effect the results ?? TLM solution using transmission line model schelkunoff model for transfer impedance
23. ## How to calculate the transfer impedance of a non-coaxial cable?

let's suppose a non-coaxial cable where the inner conductor is shifted from the main axis of the outer conductor. does there is a way to extract the transfer impedance of this cable by using the full-wave simulation ? suppose the shield is braided as shown in the image. However, the inner conductor is shifted (in the image is not shifted)
24. ## Warning 16328

i found the following warnings . what i should do?
25. ## Warning 16328

I got this Warning (Warning 16328), see the attached image, what does it mean ? should i ignore it ?
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