Yes, with 802.11n (MIMO -Multiple Input Multiple Output), an AP can have multiple radio chains (with multiple transmitter & multiple receiver antenna).
For example 2700 is 3x4 MIMO with 3 spatial stream support. That mean this AP has 4 radio chains where 3 transmitter antenna & 4 receiver antenna. With those 3 Tx antenna you can transmit 3 different data streams at the same time to a client which increase the throughput by 3 times compare to single tx antenna AP.
Hope that make sense
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