Concepts and Features
R&S
®
ZNC
40
User Manual 1173.9557.02 ─ 13
●
The center of the
Γ
plane (
Γ
= 0) is mapped to the reference impedance Z
0
, whereas
the circle with |
Γ
| = 1 is mapped to the imaginary axis of the Z plane.
●
The circles for the points of equal resistance are centered on the real axis and inter-
sect at Z = infinity. The arcs for the points of equal reactance also belong to circles
intersecting at Z = infinity (open circuit point (1, 0)), centered on a straight vertical
line.
Examples for special points in the Smith chart:
●
The magnitude of the reflection coefficient of an open circuit (Z = infinity, I = 0) is one,
its phase is zero.
●
The magnitude of the reflection coefficient of a short circuit (Z = 0, U = 0) is one, its
phase is –180 deg.
3.2.4.5
Inverted Smith Chart
The inverted Smith chart is a circular diagram that maps the complex reflection coeffi-
cients S
ii
to normalized admittance values. In contrast to the polar diagram, the scaling
of the diagram is not linear. The grid lines correspond to points of constant conductance
and susceptance.
●
Points with the same conductance are located on circles.
●
Points with the same susceptance produce arcs.
The following example shows an inverted Smith chart with a marker used to display the
stimulus value, the complex admittance Y = G + j B and the equivalent inductance L.
Screen Elements
