Log periodic antenna radiation pattern with HFSS

[hmhmhm]

hello everyone,

I'm new to hfss, and this is my first project. I have to simulate the radiation pattern of the LPDA antenna at 670MHz (E and H-Plane). My problem is that I can't get the same results as i got with 4NEC2 and EZNEC. I have uploaded my project and the 4NEC2 results. So if anyone with experience in this area could maybe check the project and tell me where i went wrong?
It would really help me a lot.
Thank you in advance.

 

[rfmw]

Don't expect superior performance with that kind of feed (open coax line)

You should modify your feed structure for the correct excitation of the LPDA.

 

[hmhmhm]

hi rfmw,

thank you for your quick replay. As I sad I'm really new to hfss, and I don't know exactly how to feed the antenna. Could you please explain it to me so that I can fix it, or could you modify my project and uploud it again. I know that I may be asking for too much, but I'm stuck at this point and I'm running out of time.

 

[e_m_c]

Basically you need to put excitation port between top and bottom parts of the antenna model. In real antenna usualy feeding coaxial cable is placed inside of one of the parts, and at the antenna top point shield of coaxial cable is connected to let say top part and the inner conductor is connected to the bottom part of the antenna - so the source (port) is practically placed between these two parts.

Attached are pictures of your antenna in MoM module of EMC Studio .

You can also take a look on these examples: **broken link removed**, **broken link removed**.

 

[cnskogilam]

hi everyone,

im currently working on wif LPDA antenna, and im find difficulty in designing it..i cant figure out how to design the feeding line for the antenna..can any1 help me giving me the simulation or help me to figure out the prob..thank you