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sutton304803

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Everything posted by sutton304803

  1. I have a bit of an unusual question, but... Sometimes when I start a new simulation by modifying one which has already been run, I will copy only the .cfx (CADFEKO model file) and none of the others. I make my modifications, then re-mesh, and finally run the simulation. My question is: Is there any critical information held in the other files that I have not been carrying over that could affect the outcome of the simulation? It occurred to me that I might be inadvertently deleting some critical simulation details. Thanks, Mark
  2. I'm using an older version of FEKO for an ongoing study and would prefer not to update until the study is complete. Does FEKO have an automatic update/hotfix system, or do updates and hotfixes have to be implemented manually? Thanks!
  3. I have a pretty simple question about creating dielectric media in FEKO: Does the density of the media have any effect on the simulation other than the calculation of specific absorption rate? I'm working under the assumption that if I'm not interested in the specific absorption rate for a model, then I need not worry about the density of the dielectric media, provided the dielectric properties are accurate.
  4. Thanks tinh, Would you be able to direct me to what feature in HyperMesh can be used for this?
  5. I am having an issue where I establish a wire port using the 'middle' option for the port's location. It appears in the center of the wire as it should in CADFEKO. However, once the meshing is complete, the port has moved all the way to one end of the wire. This is reflected in the POSTFEKO geometry as well. Does anyone know what might cause this sort of behavior?
  6. Thank you, mel. However, although the manual mentions both a 'no internal impedance' and 'internal impedance' options for 'total source power', when I select the 'Power' icon under the 'Source/Load' tab in CADFEKO, there are only three options: No power scaling Total source power (no mismatch) Incident power (transmission line model) Is there a way in CADFEKO to access the additional internal vs no internal impedance settings? If not, do you know which is used by default? I'm using a 2018 version of FEKO.
  7. Thank you mel. I have moved my discussion to the HyperMesh forum.
  8. Does HyperMesh have a feature that would allow you to essentially wrap a thin mesh (like a sheet of paper) around a complex structure (like a the body of a car or something)? I am interested in running FEKO simulations on a flexible antenna that is essentially wrapped around its mounting point. I have not yet started using HyperMesh and am evaluating my options to accomplish this task, so I apologize if this question is overly simplistic.
  9. I'm trying to understand the difference between "Total source power" and "Incident power" settings when using power scaling in FEKO. My confusion arises from noticing that 'mismatch loss' and 'power loss due to mismatch' are still available analyses in POSTFEKO and are non-zero. I assume that these analyses are referring only to the amount of power that would be lost to mismatch, not how much power was actually lost? I am doing specific absorption rate studies and would like to produce a conservative estimate using the 'Total source power' setting.
  10. Is there a way in FEKO or in HyperMesh to wrap a flat mesh (for example, a thin cuboid), around a complex object so that the two meshes are in direct contact?
  11. Thanks for the info. That helps a lot!
  12. I'm trying to model a real antenna with a similar feed structure to that shown in the attached photo. Right now, I am modeling the feed as a perfect conducting wire between the two leads with a voltage source feed point at the middle of the wire. The antenna itself is modeled as a finite thickness region, that is, having four sides in three dimensions. Without explicitly modeling the feed wires of the real geometry, does anyone know of a more accurate way to model the feed? I am interested in evaluating the antenna's specific absorption rate (SAR). It is meant to be placed directly on the skin.
  13. Is it possible to create an infinite dielectric object in FEKO? That is, an object with a defined upper Z direction boundary, but terminating at -infinity in the Z direction and infinite X and Y dimensions.
  14. Thank you, mel. That's exactly what I was looking for!
  15. Yes, and in addition I would like to start simulating more complex geometries, like realistic human head phantoms, for which I understand FDTD is more efficient. It sounds like I will need to find a different simulation software to accomplish this?
  16. Does the FDTD solver support SAR calculations? I have been using MoM for SAR calculations and have attempted to set up my models in the same way with FDTD and am getting errors saying that SAR is not supported with the FDTD solver.
  17. In a recent simulation where I modeled a conductor as a finite thickness region (having four conducting sides rather than as a 2D plane), I received the warning: WARNING 2757: A triangle is too thick as compared to the lateral dimensions for application of the skin effect approximation My question then is: what effect does this warning have on the simulation? Does FEKO simply ignore the triangles in question? Does it attempt the skin effect approximation anyway? Or does it use some other method to solve for these triangles? Any help would be appreciated! Thanks, Mark
  18. Thank you for the reply MvdM. I know this topic is old, but I'm still struggling to understand how the conductor thickness setting works. As you mentioned, I am modelling a relatively thick conducting trace that is near the skin depth for the frequency simulated and am thus modeling it as a finite thickness region having a four-sided rectangular cross-section. In this case, would it be most appropriate to set the thickness of the top and bottom conductors as HALF the actual thickness of the trace or both the top and bottom conductors each as the ENTIRE thickness of the trace. Your input would be greatly appreciated. Thanks again!
  19. I am using FEKO to simulate a small copper antenna (approximately 3.5cm x 3.5cm). Up to this point, I have been primarily using FEKO to analyze s-parameters. However, I would now like to start doing some basic specific absorption rate (SAR) studies and would like to recreate my physical setup as accurately as possible. In the physical experiment, I am interrogating the antenna using a Vector Network Analyzer (VNA) set to output 10dbm (0.01W) of power. My question is, what voltage/power settings should I use to simulate this power source? I am relatively new to electromagnetic simulations, so I apologize if the answer is obvious. My thought is to use power scaling settings set to transmission line model with 50 ohms of real impedance and 0 of imaginary (assuming a lossless transmission line). I would appreciate any input. Thanks!
  20. Just a simple question: I know that creating a union between two objects in CADFeko will ensure that their meshes don't clash. That said, does creating a union have any additional effects on how the solver treats the two objects? I ask because computation times seem to be considerably longer and results quite different when nearby objects are unioned, even thought they aren't in direct contact. Is this simply due to the increase in mesh size/complexity? Thanks!
  21. I just getting started with FEKO and I need to add some real conductors to my model. Using the default solver, I understand that I need to set the relevant volumes to free space and corresponding faces to the desired conductor. However, I am a little confused on how to go about the "thickness" setting. If I am dealing with a thick conductor, my understanding is that I simply pick a value that is greater than skin depth for the metal and the simulation frequency. Is this correct? Also, in several of my simulations, the thickness of the metal in the model is actually less than skin depth. In order to model these realistically, what thickness do I need to set for the face material? Should I use the actual thickness of the metal for both the top and bottom faces? Half the real thickness for the top and bottom faces? Or the full thickness for the top face and no material set for the bottom face? Any insight would be greatly appreciated. Thanks!
  22. I'm just starting out with FEKO and am new to modeling in general. The answer is probably obvious, but I have joined several objects in my CADFeko model together in a union and would now like to undo that union so that I have separate objects again. However, when I right click the union, the "disassemble" option is grayed out. How do I undo a union in CADFeko? Any help would be greatly appreciated. Thanks, Mark
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