HF loop antenna on HFSS

hello guys
im a senior undergraduate student
and i suppose to create on hfss an antenna that works on the range of 10-25 MHZ

am new in this program and am somehow lost there
i made a design but its not working probably

when am checking the z11 and z22 "i have 2 ports to feed the antenna"
am not getting a good answers, the imaginary part in z11 is not crossing the 0
and in z22 im getting a negative resistance value

i should get something near to 50 ohm


thanks in advanced

Hi hasan_lebnani,

A couple questions:

Wave port or lumped port? There should only be one.
Resonant Loop or Shielded Loop?
What university do you go to that they have HFSS for undergrads? Wish I would have gone there

i want to use lumped port
its resonant loop i want to send signals through it

actually we dont have HFSS courses, but my dr advised me to used it and learn it

Okay, so you should only have one port, which covers both the connections of the loop. Once this is done and run, confirm that the lumped port is exciting the correct mode by viewing the fields on the port. If the fields are correct, you must have the incorrect size, and most likely you can use optimetrics to find the correct dimensions.

Are you sure your loop is resonant? Electrically small loops are inductive. To create a resonance a capacitor is added later (not included in the EM model).

Yes its resonant

how to add capacitor?

I want to have a 75 ohm impedance
I tried many dimensions, but the les one I got 300 ohm

hello guys
i want to connect my loop antenna to a coaxial cable in hfss
could anyone help!

I'd be happy to help. What do you need help with?

thanks alot

i know how to design the antenna
and how to design the coaxial but i cant connect them together

my antenna radius is 2.5 cm
and the coaxial jacket is arround 5mm
what shall i do?

A simple way is to break the outer coax jacket and attach it to one end of the loop, while attaching the coax pin to the other end.

You could also create a balun by branching the coax (both the outer and the inner), and making one arm half a wavelength longer than the other, connecting both coax pins to either end of the loop.

Can I ask why you have a coax feed? If it's not necessary, you could just feed the loop directly from a wave port.