Carl the 3500 series APs are 802.11n 2x3:2 MIMO APs. What this means is that there are multiple transmit and receive antenna elements. On the 3500 series there are 2 transmit and 3 receive antennas and 2 spatial streams.
Take a look at the 3500 series page for more information:
You like 6 antennas. Wait till 802.11ac comes out ... ! HAHAHA
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