Sceptical
AFIK the idea of OAM is the polarisation is rotating. Now you can generate any polarisation by taking a pair of orthogonal antennas and driving them with the appropriate amplitude & phase
You get linear at any angle if the phase shift is zero, with the angle determined by the magnitude of the two drives.
You get circular with LHCP or RHCP depending on the phase being +/-90 deg.
So if you were to drive the amplitude in a cyclic manner you would get the appearance of a rotating linear phase, and if at the receiving end you were to combine the similar antennas with a matching cyclic ratio then bingo - you have the original signal as if it were received by a rotating antenna.
But how is that different from any classical modulation on dual polarisations? Sure they might be claiming the equivalent of higher than QPSK-like "polarisation constellation" points, but that is not without a loss of orthogonality and hence some cross-talk and loss of SNR.
The real question then is can such a scheme deliver any better then just going to higher RF modulation constellations on two classical orthogonal polarisations?