WiFi / Bluetooth Antenna

You will notice a trace on the main PCB coming out under the Panasonic board, and connected to the ground through a curved PCB trace with a couple of components (likely resistors, although I may be wrong here) - this is the antenna, directly etched on the PCB. It faces the front right corner of the device. The design is a 1x1 802.11n, with 150mbps max BW. The Boadcom IC supports shared antenna for BT/WLAN, so only one antenna is necessary (although there is no indication that BT is fully functional and the software stack available). We can imagine that the BT function will be enabled once accessories are available- nunchuck anyone?

This is a bit different than the implementation from the iPad where two antennas are used, although they likely perform antenna switching, not diversity, leading to the same maximum bandwidth. The idea is to chose the antenna with the best reception, less at issue with ATV as the device will remain in a fixed location.

The likely reason for Apple to use a Panasonic board instead of implementing the circuit directly on the main board is time to market. Each WLAN/BT module has to be certified, which takes time. By using a pre-certified board, Apple cut down the development time as the main PCB itself does not need to be certified. This is a common strategy for notebooks and desktops, unfortunately not possible on iPods/iPads/iPhone products due to space constrains. Additionally, and this for the iPhone, the 2G/3G section needs to be certified as well, so the WLAN certif is done in parallel and does not impact development time.

Hope this helps.