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. View attachment Project6.zip
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