Unable to use 5GHz WIFI on an XPS 13 in Ubuntu 14.04

Under Ubuntu 14.04 the Intel 7260 WIFI card in  my XPS 13 will not connect to 5GHz WIFI routers. Under Ubuntu 12.04 it connected to both 2.4GHz and 5GHz routers without problems.

Is there a software or configuration fix for this? Alternatively, is there a compatible internal WIFI card that I could buy and install in place of the current one, that would work better?

Thank you.