Due to the potential capacity-boosting for wireless communications, radio vortex wireless communication (RowComm) over orthogonal states/modes of orbital angular momentum (OAM) has been paid much attention to in recent years. A uniform circular array (UCA), as an efficient and convenient antenna structure, can transmit/receive multiple OAM beams with different OAM-modes simultaneously when the transmitter and receiver are aligned. However, for high-order OAMmodes, the OAM beams are divergent acc
