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Is 77G-81GHz freq band free of license for mmwave radar?

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tony_lth

tony_lth

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Hi, Gurus,
In Bosch mmwave radar FCC-ID report on MRRevo14F NF3, its freq band is 76-77GHz.
But in Bosch datasheet on 3QF, with the same ID, i.e. MRRevo14F, it syas the antenna gain is 23dBi.
There is 2 TX antennas in 3QF, I guess one is for far field with 76-77G, and the other is for near field with 77-81G.
But there is no 77-81GHz info on the FCC report.
I checked ITU-R standard on 76-81G, and it says 77-81G antenna gain is 23dBi.
So I guess 3QF should use 77-81G for near field, although there is no 77-81G info in FCC report.
Maybe the report is earlier than the 77-81G standard, or 77-81G is free license?
Right?
Attachment R-REC... is the ITU standard.
Attachment en_302264... is the ETSI standard.
Attachement MRRevo14F is the radar spec.
And the antennas picture.
Best,
Tony Liu
 

Attachments

  • R-REC-M.2057-1-201801-I!!PDF-E ITUR 76-81G.pdf
    583.5 KB · Views: 125
  • en_302264v020101v SRR 77-81GHz.pdf
    90.9 KB · Views: 190
  • MRRevo14F Spec.pdf
    414.3 KB · Views: 120
  • antennas.JPG
    antennas.JPG
    148.8 KB · Views: 114

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    tony_lth

    tony_lth

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With the given antennas from the Bosch circuit, it is practically impossible to have the same 23dBi gain in both, long range (76-77GHz) and low range (77-81GHz).
I think the 23dBi TX gain (ITU-R, page 4) is just a maximum recommended antenna gain (as the name of the document is: Recommendation ITU-R).

The 10dBi antenna gain for short range radar, that is shown on TR 103 593 (from FvM) Table C.1, make more sense.

Some manufacturers, use for long range TX antennas 3 raw of a series fed array, and for short range use only one raw of a series fed array (from the same array). In this way, in short range, the gain of the antenna will be lower and beamwidth wider.
 

    tony_lth

    tony_lth

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