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GUI Reference
R&S
®
ZNA
475
User Manual 1178.6462.02 ─ 12
Char. Imp.
The characteristic impedance or reference impedance ("Char. Imp.") Z
0
for the connec-
tors is a critical value that has an impact on various parameter conversions. Z
0
enters
into:
●
The calculation of the S-parameters for the calibration standards associated with
the connector type, if they are derived from a circuit model (see
●
The calculation of the (default) reference impedances for balanced ports (see
●
The calculation of impedance and admittance parameters (see
Chapter 5.3.4, "Admittance Parame-
Remote command:
[SENSe<Ch>:]CORRection:CONNection
Line Type / Rel. Permittivity εr / Cutoff Freq. fc
"Line Type" describes the wave propagation mode (offset model) in the transmission
lines of the standards associated with the connector type.
●
If the calibration kit standards contain lines with transverse electric propagation
mode (TEM, e.g. coax cables), then the "Rel. Permittivity εr" of the dielectric can be
defined. The default permittivity is the value for air. TEM-type lines have no cutoff
frequency.
●
If the calibration kit standards contain waveguides, then the lowest frequency
where a wave propagation is possible ("Cutoff Freq. fc") can be defined. The
default cutoff frequency if 0 Hz (propagation at all frequencies). No relative permit-
tivity is needed for waveguides.
Note:
The impedance for waveguides is frequency-dependent. If a waveguide line type
is selected, various dialogs indicate "varies" instead of a definite impedance value.
Impact of line type parameters
The line type parameters are used for the calculation of the S-parameters for the cali-
bration standards associated with the connector type, if they are derived from a circuit
model (see
"View / Modify Cal Kit Standards Dialog"
●
For TEM-type lines, the relative permittivity ε
r
is needed for the conversion of a
ZVR-type "Loss" (in units of dB/sqrt(GHz)) into an Agilent-type "Offset Loss" (in
units of GΩ/s) and vice versa (see
"View / Modify Cal Kit Standards Dialog"
on page 480). The "Electrical Length" and "Delay" values in the
are directly entered and therefore independent of ε
r
.
●
For waveguides, the low frequency cutoff frequency f
c
is important because no
wave propagation is possible at frequencies below f
c
. If a standard is measured to
acquire calibration data, the analyzer checks the low frequency cutoff. If the start
frequency of the sweep range is below f
c
, an error message is generated.
The offset model parameters are not used except in the context of calibration. The off-
set parameter definitions are based on independent ε
r
Remote command:
[SENSe<Ch>:]CORRection:CONNection
Cal Softtool