The characteristic modes that were calculated are all non-radiating

ferdaousAbderrazakLajili

Hi, 

I am a biginner and not used to use feko. I have this article below calculating modal Q factor for antennas. I want to obtain those results in order to apply them on my works. So here; I have a lot of problems since the characteristic modes that were calculated are all non-radiating: 

1- here ; the author is using an arlon substrate .. I'm not really sure if I made the right work ..

2- I want to excite the antenna with a coaxial cable. So I will be so thankfull if you can explain to me how to do it on feko 

3- if I made other mistakes please indicate them ..

Best Regards

Ferdaous

Unable to find an attachment - read this blog

Johan_Huysamen

Hi ferdaousAbderrazakLajili

 

I noticed two issues with your FEKO model:

1. There are small gaps between your ground and antenna trace faces and the substrate. You should create these faces to lie exactly on the substrate surfaces
2. You have the frequency range set as being from 0.4 to 10. Note that these values are in Hz. Maybe you want 0.4 to 10 GHz and should therefore enter 400e6 and 10e9 respectively. In the paper - as seen in Fig. 3 - 100MHz to 2 GHz (100e6 and 2e9) was used.

For creating a coaxial excitation you have various options on FEKO. For the most accurate representation I would suggest physically building a short coaxial section (inner and outer conductor cylinders with a dielectric region in between. Using the default Surface Equivalence Principle (SEP) this can then be excited either by a Waveguide Port on the back coaxial face or by an Edge Port located between the inner and outer conductors. (Note that the Waveguide Port might not be supported with the Characteristic Mode Analysis in FEKO).

 

For examples on these and other ways of feeding antennas, take a look at the FEKO Examples Guide (ExampleGuide.pdf located in the \help\feko\pdf folder of your Altair installation).