Apple AirPort Time Capsule A1470 (2 TB, ME177LL/A)

Wikidevi Notes
3x3 MIMO Base Station

Teardown on iFixit

The FCC test report indicates the firmware used during testing was 6.10.56.166. This would seem to indicate the use of wl.. and thus Broadcom Wi-Fi radios..
 * Transmit beam forming is supported on 802.11n/ac