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The following section from ST Micro's AN4974 - 'Antenna Matching' app note is a bit of a mystery.

Is there a VNA / network analyzer guru out there who can tell me what the 4th line there is saying? I don't understand the jargon. I'm familiar with the short/open/50ohm termination method of calibrating a VNA, and I know a minimum about S(i,j) parameters, Smith charts and such. They're using a single-turn standard coil to examine a multi-turn tag coil via induction.

7.3 Verification of the Q factor in the frequency domain The Q factor can be measured using a vector network analyzer and an ISO10373-6 Class 1-3 calibration coil.

  1. The network analyzer shall be calibrated for a frequency sweep from about 10 to 20 MHz
  2. S11 measurement in log mag format shall be displayed.
  3. The calibration coil is connected to the VNA.
  4. “Short” calibration of the coil and conversion to “Z: Reflection”
  5. Set marker 1 and enable the bandwidth/Q factor measurement
  6. Place the PCD antenna on the measurement coil
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  • \$\begingroup\$ Can you provide a link to the full document? \$\endgroup\$
    – The Photon
    May 30, 2022 at 15:31
  • \$\begingroup\$ It might mean short as opposed to long, full or thorough, rather than short as opposed to open. After all, it's only measuring a ratio of frequencies, not an accurate power level. \$\endgroup\$
    – Neil_UK
    May 30, 2022 at 15:47
  • \$\begingroup\$ st.com/resource/en/application_note/… \$\endgroup\$ Jun 10, 2022 at 21:28
  • \$\begingroup\$ I'm told by ST that "The idea is to calibrate away the characteristics of the pickup coil, and be able to only sense the characteristic of the reader or tag antenna - since the antenna is still connected during the "short" calibration." \$\endgroup\$ Jun 21, 2022 at 23:37

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