Greetings,

I have a Wiltron (Anritsu) VNA Type N Calibration Kit, Model 3653 and am trying to derive the calibration coefficients that will work in the HP/Agilent VNA Standard Definition table.

Wiltron provides an offset length, 20.3700 mm, and the C0 . . . C3 and L0 . . . L3 values. The C and L values are in the proper terms for the table but I have to compute the values for Offset Delay and Offset Loss using the physical length given by Wiltron. I understand the equation for the offset delay and have computed a value that appears resonable; 6.7969E-11.

Unfortunately, I don't understand the operations / variables involved in the offset loss equation. I understand that I need to know the dielectric constant or the velocity factor of the transmission line in the standards. A visual check indicates that the dielectric is air. Even so I am stumped.

I have been working out of various HP / Agilent manuals and Ap Notes and have found Ap Note 1287-11 most helpful. Also, the Agilent Technical Contact Center has given me some guidance via email.

Anyone willing to help me out?

Thanks in advance.

Wally Rice

Environ Laboratories LLC

Minneapolis, MN

I have a Wiltron (Anritsu) VNA Type N Calibration Kit, Model 3653 and am trying to derive the calibration coefficients that will work in the HP/Agilent VNA Standard Definition table.

Wiltron provides an offset length, 20.3700 mm, and the C0 . . . C3 and L0 . . . L3 values. The C and L values are in the proper terms for the table but I have to compute the values for Offset Delay and Offset Loss using the physical length given by Wiltron. I understand the equation for the offset delay and have computed a value that appears resonable; 6.7969E-11.

Unfortunately, I don't understand the operations / variables involved in the offset loss equation. I understand that I need to know the dielectric constant or the velocity factor of the transmission line in the standards. A visual check indicates that the dielectric is air. Even so I am stumped.

I have been working out of various HP / Agilent manuals and Ap Notes and have found Ap Note 1287-11 most helpful. Also, the Agilent Technical Contact Center has given me some guidance via email.

Anyone willing to help me out?

Thanks in advance.

Wally Rice

Environ Laboratories LLC

Minneapolis, MN

The offset loss term for computation is found starting on page 7 of Ap Note 1287-11. Note the offset loss term accounts for skin effect loss of the metal walls. Does the Wiltron definition include any loss term? If so I would suggest computing their offset loss at a particular frequency--say 1 GHz using their model (by the way there is a good chance it will be the same model) then use the equation in Ap Note 1287-11 to compute equivalent value.