Measurements of 3.5 GHz OAM Misaligned Channels in Indoor Corridor Scenarios

This paper presents measurements of OAM misaligned channels in an indoor corridor using a spectrum channel sounder. The channel sounder consists of 3.5 GHz eight-element OAM antennas with +1 and −1 modes and a vector network analyzer. First, the large-scale propagation loss of the transmission distance
$3\lambda\sim 20\lambda$
was measured when the transmitter and receiver were aligned. Then, the received power was measured when receivers were misaligned at different horizontal axis offset angles. In addition, the measurements of the conventional monopole in the identical setup were given as reference. The results show the measurements agreements with the theoretical derivation of propagation loss trends in both aligned and misaligned cases. Moreover, the results also suggest the overall performance of OAM may significantly degrade when the beam diverges as increasing propagation distance.