Antenas Mimo

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http://dx.doi.org/10.1109/TAP.2011.2173142

MANUSCRIPT ACCEPTED FOR PUBLICATION IN IEEE TRANSACTIONS ON ANTENNAS ANDPROPAGATION (SEE COPYRIGHT NOTICE ON PAGE 1)

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Is orbital angular momentum (OAM) based radio communication an unexploited area?
Ove Edfors, Member, IEEE, and Anders J Johansson, Member, IEEEAbstract—We compare the technique of using the orbital angular momentum (OAM) of radio waves for generating multiple channels in a radio communication scenario with traditional multiple-in-multiple-out(MIMO) communication methods. We demonstrate that, for certain array configurations in free space, traditional MIMO theory leads to eigen-modes identical to the OAM states. From this we conclude thatcommunicating over the sub-channels given by OAM states is a subset of the solutions offered by MIMO, and therefore does not offer any additional gains in capacity. Index Terms—Antenna arrays, antennaradiation patterns, channel capacity, free-space propagation, MIMO, orbital angular momentum, radio communication.

I. I NTRODUCTION T WAS recently shown that the photon orbital angular momentum (OAM)can be used in the low frequency radio domain and is not restricted to the optical frequency range [1]. These findings and the claimed prospects for opening a new frontier in wireless communications,with “promise for the development of novel information-rich radar and wireless communication concepts and methodologies” [1], motivates the investigation in this paper. Here we focus on the wirelesscommunication aspects of [1] and the follow-up paper [2]. We start by identifying the conditions under which electromagnetic waves with specific OAM characteristics1 are generated in [1] [2] and continueby comparing with properties of traditional communication using multiple-in-multiple-out (MIMO) antenna systems [5] [6] [7]. We pay special attention to the singular value decomposition (SVD) based...