For some strange reason, wifi connectors are not compatible with normal
SMA coax connectors. The center pin is a male in an otherwise female
connector. And visa versa.

But you probably have accumulated a few wifi "rubber duck" antennas.
Inside the plastic "duck" is just some thin teflon coax cable and a
dipole antenna with a 1/4 wave shroud around the coax and 1/4 wave
exposed center conductor. It's easy to separate the plastic duck off
the antenna, just bend it at the joint just above the elbow and it
should just pop off. Being teflon, you don't have to worry about
melting it with the soldering iron. This coax looks to be 50 ohm
impedance. Get a BNC connector and attach it like you would to coax of
this thin type. To deal with the extra thin coax, I used a small
solderable metal washer to give the shield clamping connector pieces
(the funny looking washers) something to grab when you tighten the
threaded on the outside bushing you tighten into the connector. As the
connectors I had were meant for fatter coax. Don't forget to place the
washers and such on the coax before you solder the washer to the coax
shield.

As a test, I inserted two such adapters into the feedline for my wifi
antenna, and looked at the wifi utility software window that reports
signal strength, and saw no desernable extra signal loss (less than a
dB). (I scrapped out a bad wifi booster module to get its reverse SMA
connectors to get the mate for the antenna side connector)

Once you have built this adapter, you can then use regular good quality
coax cable with BNC connectors (or N or other connector good for
microwave work) to connect a homebrew wifi antenna to the wifi computer
card. There's also a ham band that shares part of the wifi band, so we
could conceivably run high gain high power ham to ham using wifi based
equipment.