5 CALIBRATION AND CALIBRATION KIT
Two-port model is used for the standard THRU/LINE (See figure 5.5).
Figure 5.5 Two-port standard model
The description of the numeric parameters of an equivalent circuit model of a
calibration standard is shown in table 5.3.
Table 5.3 Parameters of the calibration standard equivalent circuit model
(as in the
For a one-port standard, it is the offset impedance (of a
transmission line) between the calibration plane and the circuit
with lumped parameters.
For a two-port standard, it is the transmission line impedance
between the two calibration planes.
The offset delay. It is defined as one-way propagation time (in
seconds) from the calibration plane to the circuit with lumped
parameters or to the other calibration plane. Each standard delay
can be measured or mathematically determined by dividing the
exact physical length by the propagation velocity.
The offset loss in one-way propagation due to the skin effect. The
loss is defined in Ω/sec at 1 GHz frequency. The loss in a
transmission line is determined by measuring the delay T [sec] and
loss L [dB] at 1 GHz frequency. The measured values are used in
the following formula:
[ ] 
Offset (transmission line):
§Z0 – impedance;
§T – propagation delay;
§Rloss – loss.