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Mizum.1
Visitor II
April 20, 2020
Solved

About the receiving circuit of EVAL. What should I connect to the antenna? CIR or Coupler. Is LNA unnecessary?

  • April 20, 2020
  • 1 reply
  • 745 views

In Figure 2 of st25RU3993 DateSheet, the CIR is used in front of the antenna, but the coupler is used for T4 of EVAL.

I think if I want to use carrier cancellation, ​the Coupler needs to be used.

Which one is recommended?

​

​

Is LNA unnecessary?​

Does adding LNA increase the sensitivity?

Please tell me NF or device noise.

    This topic has been closed for replies.
    Best answer by Bart Herse

    Hi Mizum.1,

    Indeed , carrier cancellation requires a directional coupler. A 10 dB directional coupler is recommended. A 5 dB coupler would be possible as well but beware of the significant higher transmission losses that come with it. Components we have made experience with are from Anaren, Johanson Tech and RN2 although other manufactures might have suitable models too.

    An LNA can help to boost the sensitivity but I recommend to use a model with a bypass.

    Cheers,

    B

    1 reply

    B
    Bart HerseAnswer
    Visitor II
    May 4, 2020

    Hi Mizum.1,

    Indeed , carrier cancellation requires a directional coupler. A 10 dB directional coupler is recommended. A 5 dB coupler would be possible as well but beware of the significant higher transmission losses that come with it. Components we have made experience with are from Anaren, Johanson Tech and RN2 although other manufactures might have suitable models too.

    An LNA can help to boost the sensitivity but I recommend to use a model with a bypass.

    Cheers,

    B

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