Short answer:
That looks like a inverse polarity SMA conector.

Long answer:
What you need is a cable that goes from a reverse polarity SMA plug to whatever conector the bicuad antenna has.

You can buy a custom cable at:
Custom Cable and Pigtail Ordering

If you what to do it your self, what you need is a reverse polarity SMA plug, a conector for the bicuad antenna, the cable and the crimp tools.

You can buy them at hyperlink, here is a link (look under the Reverse-Polarity SMA-Plug Crimp Connectors title):
Reverse-Polarity SMA-Type / RP-SMA / RSMA Connectors

Crimp Tools
Crimp Tools and Cable Strippers