System Overview
R&S
®
ZVT
61
Getting Started 1300.0045.62 ─ 10
3.2.4.3
Polar Diagrams
Polar diagrams show the measured data (response values) in the complex plane with a
horizontal real axis and a vertical imaginary axis. The grid lines correspond to points of
equal magnitude and phase.
●
The magnitude of the response values corresponds to their distance from the cen-
ter. Values with the same magnitude are located on circles.
●
The phase of the response values is given by the angle from the positive horizontal
axis. Values with the same phase are on straight lines originating at the center.
The following example shows a polar diagram with a marker used to display a pair of
stimulus and response values.
Example: Reflection coefficients in polar diagrams
If the measured quantity is a complex reflection coefficient (S
11
, S
22
etc.), then the cen-
ter of the polar diagram corresponds to a perfect load Z
0
at the input test port of the
DUT (no reflection, matched input), whereas the outer circumference (|S
ii
| = 1) repre-
sents a totally reflected signal.
Examples for definite magnitudes and phase angles:
●
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.
Screen Elements
