Cascade Load Standard's Parameters in Delay

Coefficients of a Cascade calibration substrate are often in this format:

C Open: -6.5 fF
L Short: 3.3 pH
L Term: -0.4 pH
Load: 50 ohm

These are the parameters for lumped element models. The load standard has an inductance parameter in pH. But there are some cases where it is necessary to enter a delay parameter into the Load Standard. To convert L-term to delay, there is an empirical equation:

T_{Delay}=\frac{L}{Z_o}

In this equation, Zo is recommended to be very high, such as 500 Ω (normally 50 Ω).

Please note that this is an approximation. Since these parameters depend on the material of the calibration substrate, it is best to rely on the vendor’s documentation.

Click here to see the original document: Cascade Application Note – On-Wafer Vector Network Analyzer Calibration and Measurements (page 6)

Cascade Load Standard’s Parameters in Delay