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Freespace GRL Question

Question asked by pschmal on Mar 19, 2009
Latest reply on Apr 4, 2009 by stoyan_ganchev

I currently have a problem where the automatic finding of the sample holder is gating in a reflection.  The reflection is close to the sample holder in the time domain, however, when doing a SOLT and then using the transform toolbar I am able to easily gate this reflection out.  Unfortunately, since the 85071 software is not used, I don't have the coefficients calculated or applied.  So while I get a smooth trace, I am unable to get full transmission when sample holder is empty etc.  When I try to use the 85071 software, it always finds a way to gate this reflection in, ruining the calibration.  Unless I make the gate span ridiculously small, it does this.  The gate search start and stop time seem to have no effect.  I have even set these numbers so the sample holder is not included at all, yet it comes back with the same calibration.  Is there a way to manually set the sample gate area then run the coefficient calculation part of the software?  I assume whatever sample area it finds, it considers all other areas outside of the gate to be 'antenna' areas and assigns these to the calibration coefficients O11 and T11 as in [1].  Is this correct?

Thank you for your help,

[1]  Improved Free-Space S-Parameter Calibration
Bartley, P.G.; Begley, S.B.
Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE