All 802.11n devices supporting the 5G band support at least a bandwidth 20 MHz (as well as 40 MHz). In addition, you can use 5 and 10 MHz as well on some Athero

All 802.11n devices supporting the 5G band support at least a bandwidth 20 MHz (as well as 40 MHz). In addition, you can use 5 and 10 MHz as well on some Atheros devices with open source drivers.