As far as I know it is integrated in the window. If you are referring to the button type connector, I doubt that you can get that separately. I had to glue mine back on after the vehicle went for a valet and they ripped it off. I at least had all the parts, and I used a special glue designed to stick aerials to windows.
Not sure if the aftermarket aerials have a button,but in my experience the origianl old wire whip aerials are best. You can put one like that on the roofrack or drill a hole :evil: in thew fender and mount it there.