Hi Dave:
I stand corrected, you can not measure phase angle with a SNA, but you can make a more accurate |S11| measurement with the SNA.
An air line is very different from a sliding load. If a sliding load is used as part of the VNA calibration the resulting measurement will be better than the common OSL type cal.
Note, VNA cal standards come with data, but the data is generic to the model number of the set, NOT to the serial number, hence you can call up cal standards in the CAL menu of the VNA.
There's a Wiltron (Anritsu) app note "Reflectometer Measurements - Revisited" (11410-00214) on using the air line and mismatched load to determine reflectometer directivity. From the app note:
"The effective directivity after a broadband load calibration is essentially equal to the return loss of the load used for calibration. Unless the user is certain that the return loss of the load is at least 15 dB greater than return loss of devices to be measured, significant errors can result. Sliding loads are recommended for calibration and VNA test port specifications are based upon sliding load calibrations."
So, if the desired impedance of the DUT is 50.0 +0j then using the airline measurement method with a SNA will give more accurate results.
--
Have Fun,
Brooke Clarke, N6GCE
