Battery died when I was away. Now can’t find the AirTag. Have the bag it was in.

As the title says my AirTag battery died while I was away. I actually got one notice the battery was low when I got home. The next day I went to find it and I could not locate it in the camera bag I used to keep it in. I have torn the bag apart and don’t think it’s still in there, but I have a vague memory of thinking I had a clever hiding spot. Is there any sort of NFC or other passive scan that works without battery power? How do I use it if there is? It was last in my house so I know it’s somewhere nearby.