ath9k is a 100% free wireless driver for Atheros IEEE 802.11n WLAN based chipsets.

Supported chips:

· AR5418+AR5133
· AR5416+AR5133
· AR5416+AR2133
· AR9160
· AR9280
· AR9281

Enabling ath9k:

To enable ath9k, you must first enable mac80211:

Networking --->
Wireless --->
< M > Improved wireless configuration API
< M > Generic IEEE 802.11 Networking Stack (mac80211)

You can then enable ath9k in the kernel configuration under

Device Drivers --->
[*] Network device support --->
Wireless LAN --->
< M > Atheros 802.11n wireless cards support

Product's homepage