HFSS Slot antenna problem
I am working on a problem lately without any success.
I am simulating on HFSS a slot antenna which is located on the air/dielectric (silicon, er=11.7) interface.
I try to calculate the radiation pattern in the dielectric half-space but the directivity I am getting is very low compared to what I am expecting.
For example, for a typical double slot antenna, max directivity should be around 10dB and I get 4dB.
I have the same problem with every slot antenna I simulate.
FYI:
I conducted the runs using both absorbing boundaries or PML.
I tried also having the metal surface finite (smaller than the air/dielectric box)
or letting it protrude into the absorbing boundary or PML.
Do you have any suggestions?
Thank you.
Can you upload the design file. What type of port you are using. Are you using PEC as antenna conductor material?
I used lumped port and PEC as the antenna conductor.
Thank you.
1. If you are using a double slot antenna with more than one port, make sure that the excitation phases are correct.
2. Silicon is a VERY lossy substrate, try comparing the same antenna using metal over air (radiating slot) and compare to text book exact solution (e.g., Balanis).
When you have a good agreement between the solutions change back to silicon
Thanks for the response sharonma.
I doubt the problem is the silicon substrate because in the HFSS model I am using conductivity of silicon is set to 0.
I am also using one lumped port excitation.
Thank you.