4/spl times/4 MIMO transceivers for civilian wireless communications

This paper presents the implementation and characterization of a 4/spl times/4 multiple input multiple output (MIMO) RF transceiver that operates at ISM frequency band of 2.45 GHz. The design is implemented using low cost commercially available off-the-shelf components (COTS). The system benefits from direct conversion transceiver units, a common phase-locked loop oscillator, a linear 1/spl times/4 antenna array, and self-contained power supply. The transceiver measurements indicate a good overall system performance in terms of dynamic range and constellation diagram (QPSK and 8PSK modulation formats) for both transmit and receive modes.