Study on MIMO Communication using Microwave Guided-Modes Propagating along PVC Pipe Wall

We investigated MIMO communication using a PVC pipe wall as a communication path. We attached two antennas to both end faces of 1-m-long PVC pipe, and evaluated its transmission characteristics. When the antenna was installed on the cross section of the PVC pipe, S21 at 5 GHz was about −25 dB, which was more than 15 dB higher than that in case antennas are set inside the pipe and in free space. MIMO channel capacity becomes maximum (0.98 bit/s/Hz) when the antennas were placed at the same positions at both end faces on the diagonal line of the pipe.