hfss excitation

Hi,

I am a freshman in EM engineering and I just start using HFSS to simulate some antennas. However, I have some questions about assigning excitations. I had drawn a dipole structure in HFSS but have some problem on assigning excitations. I want to excite it from air and see what is the impedance of the antenna. Should I use plane wave excitation or assign wave port from outside?
Also, if I put a lumped port in between the two arms and excite it that way, do I get the same result? since the antenna is reciprocal......

These questions had bothered me for weeks...

Thanks so much...

Ng

I am usually not dealing with antennas, but try to use wave port, not lumped one.
When simulating microstrips, I have found gap ports to be unreliable

Hope tihis helps.
:D

Hi,

Thanks for the reply.

However, if I put a wave port at the most outer box and excite my antenna, how can I measure the antenna impedance? Or do I need to measure the current and voltage separately?

Thanks again!

Ng

If your dipole is folded on a dielectric material without ground plane, you can use a lumped port placed inside the gap. It is like placing a voltage source inside the gap, with its positive terminal connected to one leg of the dipole and the negative one connected to the other leg. Your dipole must be enclosed into an airbox with radiation boundaries (all radiation walls must be separated of λ0/4 at least from the dipole). Define a far field infinite sphere if you want to plot radiation characteristics as well. Try with a half wavelength dipole. You should see a Z11 which is coherent in value with the one of the classical λ/2 dipole (around 70+j40 ohms). Expect some variations due to differences between a thin wire dipole and a folded dipole structure.

Regards

generally, using lumped port in dipole model,and also you can observe the impedance in results