Hello ccstii and welcome to the community.
It is not totally clear to me what type of surface you are trying to install your base and post to. What is your half wall material and is that where you would like to install your curtain? If that is the case you may consider a post base that is anchored to the solid half wall using concrete anchors.
For example a 1/2” black iron flange, found in the plumbing department can be affixed to a solid surface. Then a pipe cut to whatever length you need, can be screwed into the flange.
Or if you would like something a bit more decorative see the picture below of an aluminum pier base for a post light and use an exterior lamp post.
Decorative Post Base
One type of anchor screw is the Tapcon. You will have to predrill the hole for the anchor using a Tapcon bit. Select the box with the arrow to view a descriptive video on how to install these anchors.
Tapcon Anchor Screws
If you have more details to share, I would like to hear back from you. I may have more options for you
I am a Home Depot associate trained and authorized to help people on the internet.