AC/BGN Compatibility

I'm looking to replace my Intel 2230 card because it seems to have connectivity issues in my laptop. I've been looking for a new card but can't seem to figure out whether to buy a "AC-type network card". They all seem priced fairly but if I don't have an AC router and I connect to public (campus) wifi so I don't really understand if they are backwards/forwards compatible. Thanks


Laptop: Lenovo U410. Any miniPCIe network card suggestions would be helpful too.

All ac wireless cards have compatibility at the very least with 802.11g so you will be covered with any Wi-Fi you are near be it g, n, or ac. You will have compatibility with an ac card