λ/16 spaced single RF chain MIMO antenna using low-power CMOS switches

A single RF chain multi-input multi-output (MIMO) antenna using low-power CMOS switches is presented for beam-space transceiver systems. A discrete switch simplifies the design and implementation of reconfigurable loads and DC bias circuitries, and does not require complicated external matching components. The proposed approach also provides a compact antenna structure optimized for multiplexing multiple signals. The measured reflection coefficient, peak gain, and total efficiency of the antenna are -12 dB, 3.9 dBi, and 85%, respectively. The over-the-air experiments for multiplexing two binary phase-shift-keying signals at 2.45 GHz are performed to confirm the effectiveness of the implemented antenna. The corresponding error vector magnitude of the first and second data stream shows 20.6 dB and 16.7 dB, respectively.