Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’
We show that the public experiment held in Venice by Tamburini et al and reported in 2012 New J. Phys. 14 033001 can be regarded as a particular implementation of multiple-input–multiple-output (MIMO) communications and, therefore, has no advantages over established techniques. Moreover, we explain...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2012-01-01
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| Series: | New Journal of Physics |
| Online Access: | https://doi.org/10.1088/1367-2630/14/11/118001 |
| _version_ | 1797751682429353984 |
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| author | Michele Tamagnone Christophe Craeye Julien Perruisseau-Carrier |
| author_facet | Michele Tamagnone Christophe Craeye Julien Perruisseau-Carrier |
| author_sort | Michele Tamagnone |
| collection | DOAJ |
| description | We show that the public experiment held in Venice by Tamburini et al and reported in 2012 New J. Phys. 14 033001 can be regarded as a particular implementation of multiple-input–multiple-output (MIMO) communications and, therefore, has no advantages over established techniques. Moreover, we explain that the use of a ‘vortex’ mode (orbital angular momentum ℓ = 1) at one of the transmit antennas is not necessary to encode different channels since only different patterns—or similarly different pointing angles—of the transmit antennas are required. Finally, we identify why this MIMO transmission allowed the decoding of two signals, despite being line-of-sight. This is due to the large separation between the receiving antennas, which places the transmit antennas in the near-field Fresnel region of the receiving ‘array’. This severely limits the application of this technique in practice, since, for a fixed separation between receiving antennas, the detectable signal power from any additional vortex mode decays at least as 1/ r ^4 . |
| first_indexed | 2024-03-12T16:52:06Z |
| format | Article |
| id | doaj.art-ea388cabbe4842908717e3ece13a74df |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:52:06Z |
| publishDate | 2012-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-ea388cabbe4842908717e3ece13a74df2023-08-08T11:07:56ZengIOP PublishingNew Journal of Physics1367-26302012-01-01141111800110.1088/1367-2630/14/11/118001Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’Michele Tamagnone0Christophe Craeye1Julien Perruisseau-Carrier2Adaptive MicroNanoWave Systems Group, LEMA/Nanolab, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, SwitzerlandUniversité Catholique de Louvain (UCL) , ICTEAM Institute, Bâtiment Stévin-2, Place du Levant B-1348 Louvain-la-Neuve, BelgiumAdaptive MicroNanoWave Systems Group, LEMA/Nanolab, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, SwitzerlandWe show that the public experiment held in Venice by Tamburini et al and reported in 2012 New J. Phys. 14 033001 can be regarded as a particular implementation of multiple-input–multiple-output (MIMO) communications and, therefore, has no advantages over established techniques. Moreover, we explain that the use of a ‘vortex’ mode (orbital angular momentum ℓ = 1) at one of the transmit antennas is not necessary to encode different channels since only different patterns—or similarly different pointing angles—of the transmit antennas are required. Finally, we identify why this MIMO transmission allowed the decoding of two signals, despite being line-of-sight. This is due to the large separation between the receiving antennas, which places the transmit antennas in the near-field Fresnel region of the receiving ‘array’. This severely limits the application of this technique in practice, since, for a fixed separation between receiving antennas, the detectable signal power from any additional vortex mode decays at least as 1/ r ^4 .https://doi.org/10.1088/1367-2630/14/11/118001 |
| spellingShingle | Michele Tamagnone Christophe Craeye Julien Perruisseau-Carrier Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ New Journal of Physics |
| title | Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ |
| title_full | Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ |
| title_fullStr | Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ |
| title_full_unstemmed | Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ |
| title_short | Comment on ‘Encoding many channels on the same frequency through radio vorticity: first experimental test’ |
| title_sort | comment on encoding many channels on the same frequency through radio vorticity first experimental test |
| url | https://doi.org/10.1088/1367-2630/14/11/118001 |
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