Helical antenna in HFSS Problem

Hello
Here is my design and output result

output

That is too wrong because I expect only a endfire pattern and not two-side lobe and with a back fire lobe.
The attachment is my design file ( designed with HFSS 15). I excited the antenna with a "Lumped excitation " that excites the ground plane and helical antenna.
Project6.zip

Are you sure the radiation pattern is at the frequency of impedance matching?
And in helical antenna, is the radiator connected to the ground plane?

Could be a number of problems. Looks like you just have a helix curve that isnt a conductive material. I bet the square is radiating as a patch antenna. Do this to fix:

1. Check to make sure your units and scale is all correct.
2. Create a circle curve at the end of your helix and loft it all the way to the other end, creating a 3D helix.
3. your port definition is probably all wrong, and your helix is probably attached to your ground plane.
4. follow this https://www.youtube.com/watch?v=xY_fN4vI8f0