This paper presents wireless OAM (orbital angular momentum) and OAM-MIMO (multi-input and multi-output) multiplexing in a 28 GHz frequency band. We have implemented transmission (Tx) and reception (Rx) antennas consisting of multiple uniform circular arrays (UCAs) to confirm the feasibility. Each UCA can concurrently transmit or receive five OAM mode signals (0, ±1, ±2). Using implemented antennas, we rectified mode-selective Rx SNR degradation caused by the inherent nature of OAM beams. With a combination of antenna selection and receiver diversity we have achieved a 45 Gbps transmission rate using five OAM modes. We also experimentally demonstrated the effectiveness of the OAM-MIMO multiplexing by using a total of eleven OAM modes (three OAM 0 modes and two sets of OAM ±1 and ±2 modes). Experimental results reached a new milestone in point-to-point transmission rates by achieving 100 Gbps at 10 m transmission distance.