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shahid78
Joined: 29 Jul 2006
Posts: 156
Helped: 16
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 12 May 2008 18:38 S parameters measured by network analyzer |
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i am a bit confused on interpreting the scattering parameter results shown by network analyzer
for example the S11 shown by network analyzer for any antenna is in dB.
now if i want to calculate the abosulte values which formula should i use
S11(dB)=20 log ( S11)
or
S11(dB)=10 log (S11)
any help will be highly appreciated
regards
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Phytech
Joined: 30 Apr 2008
Posts: 23
Helped: 3
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| 16 May 2008 0:04 S parameters measured by network analyzer |
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| The first one
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citizen
Joined: 14 May 2008
Posts: 105
Helped: 4
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| 19 May 2008 7:55 Re: S parameters measured by network analyzer |
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thank you,
i was also have this doubt .
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akedar
Joined: 27 Jul 2004
Posts: 251
Helped: 13
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| 19 May 2008 8:15 S parameters measured by network analyzer |
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well S11 is measuring in terms of power so u have to take 10 log formula
because S=a/b
where a nd b are incident and reflected power waves
u can refer to manual it will further confirm
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Slayerza
Joined: 23 Oct 2005
Posts: 305
Helped: 21
Location: South Africa
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| 25 May 2008 20:53 Re: S parameters measured by network analyzer |
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I agree since the parameters are measured as power levels it should be the 10log variant. This can easily be derived from the definition of a decibel.
Cheers,
Slayer
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loucy
Joined: 26 Aug 2001
Posts: 414
Helped: 10
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| 27 May 2008 21:50 Re: S parameters measured by network analyzer |
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| S-parameter is complex (magnitude and phase) so it cotains more information than the power ratio. In any case, even if you define it as a RATIO of two powers, it doesn't have the unit of power. 10Log is incorrect.
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sasaberali
Joined: 05 Oct 2007
Posts: 19
Helped: 1
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| 28 May 2008 9:39 Re: S parameters measured by network analyzer |
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hi
20×log10×s11=s11(db)
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