The article presents a high-capacity millimeter-wave communication system that utilizes orbital angular momentum (OAM) multiplexing to transmit multiple data streams over a single aperture pair. The system achieves a spectral efficiency of approximately 16 bit s\(^{-1}\) Hz\(^{-1}\) and a total capacity of 32 Gbit s\(^{-1}\) by transmitting eight independent OAM beams, each carrying a 4 Gbit s\(^{-1}\) 16-QAM signal. The OAM beams are generated using spiral phase plates (SPPs) and multiplexed via a 1x4 combiner. At the receiver, the OAM channels are demultiplexed using SPPs and an OAM mode demultiplexer, achieving bit-error rates below 3.8 \(\times 10^{-3}\). The study also demonstrates an 8 Gbit s\(^{-1}\) link using four OAM beams on each of two polarizations, with crosstalk less than -12.5 dB. The research highlights the potential of OAM-based multiplexing to increase the capacity and spectral efficiency of millimeter-wave wireless communication links.The article presents a high-capacity millimeter-wave communication system that utilizes orbital angular momentum (OAM) multiplexing to transmit multiple data streams over a single aperture pair. The system achieves a spectral efficiency of approximately 16 bit s\(^{-1}\) Hz\(^{-1}\) and a total capacity of 32 Gbit s\(^{-1}\) by transmitting eight independent OAM beams, each carrying a 4 Gbit s\(^{-1}\) 16-QAM signal. The OAM beams are generated using spiral phase plates (SPPs) and multiplexed via a 1x4 combiner. At the receiver, the OAM channels are demultiplexed using SPPs and an OAM mode demultiplexer, achieving bit-error rates below 3.8 \(\times 10^{-3}\). The study also demonstrates an 8 Gbit s\(^{-1}\) link using four OAM beams on each of two polarizations, with crosstalk less than -12.5 dB. The research highlights the potential of OAM-based multiplexing to increase the capacity and spectral efficiency of millimeter-wave wireless communication links.