Meraki's assortment of 802.11B/G and N access points are all based on Atheros wireless chipsets. I'll show you the innards of a few so you can see what makes them tick. Figure 3 shows the FCC ID photo for the Indoor unit. Note that the current product doesn't have the RP-SMA connector shown at the left of the photo.
Figure 3: Meraki Indoor AP board
A closeup in the FCC ID docs shows an Atheros AR2315 Single-Chip 2.4 GHz Access Point Solution under the flexible black heat spreader at the center of the photo. The Indoor and Outdoor APs both have separate power connectors. The Outdoor unit comes with a PoE power injector to simplify installation, but the Indoor unit doesn't.
The popular MR14 dual-radio AP is shown in Figures 4 and 5, where you can see the radios on mini-PCI boards.
Figure 4: Meraki MR14 board top
More detailed photos in the FCC ID file show an Atheros AR7161 600 MHZ Wireless Network Processor, IC+ IP1001 single chip Gigabit Ethernet NIC and two Unex DNMA-92 802.11n a/b/g wifi 2x2 mini-PCI modules, which use the Atheros AR9220 single-chip dual-band 11n 2X2 MIMO device.
Figure 5: Meraki MR14 board bottom
The MR11 uses the same chassis and only one of the same radio modules.
Note that while both of the MR14's radios are dual-band, one handles the 2.4 GHz band while the other handles 5 GHz. Meraki says that when the MR14 is used in a mesh configuration, both radios can handle client connections, but only one is used for the mesh link. Meraki's proprietary mesh routing routine figures out the best one to use.
If you go for the three-radio MR58, then a radio can be dedicated to the mesh link, which will operate in the lower 5.1 GHz channels of the 5 GHz band.