Operating the R&S
QAR
R&S
®
QAR
44
User Manual 1178.7200.02 ─ 09
points to cover a selected frequency span between 72
GHz and 82
GHz. This allows
for an exact evaluation of the DUT's transmission frequency response.
The frequency response yields detailed information regarding the RF transmission loss
of the DUT at the exact frequency band intended for radar operation. This is therefore
independent of the actual signal waveform utilized by the radar unit, which facilitates
the testability and optimization of the radome itself.
The transmission diagram shows the frequency response of the DUT. The minimum
and maximum values indicate the degree of frequency matching achieved by the DUT.
Ideally, the minimum of the frequency response is located at the operating frequency
range of the radar sensor that is to be used in combination with the DUT. Shifted min-
ima indicate issues with the DUT's electrical thickness.
The R&S
QAR calculates the one-way mean attenuation for specific frequency ranges
(76
GHz to 77
GHz and 76
GHz to 81
GHz). The results are displayed below the dia-
gram in logarithmic units (dB).
The one-way mean attenuation is calculated as follows:
-20
·
log
10
(mean transmission coefficient)
The mean transmission coefficient is calculated over the respective frequency range.
You can also query the minimum attenuation (and its frequency) using SCPI com-
mands. For details ,see
Chapter 6.2.4.2, "Measurements (12 Cluster)"
5.1.4
Configuration
The R&S
QAR provides several tools to configure the radome measurement.
Working with evaluation masks
The evaluation mask available for the reflection measurement defines the area that is
evaluated for the mean reflection and the standard deviation of the reflection measure-
ment.
1. Select "Edit Mask".
In editing mode, you can change the shape and location of the evaluation mask.
2. Move, delete or design an evaluation mask.
a) Move the mask by dragging it around with the mouse and dropping it in its new
location.
b) Delete a selected mask with the "Del" key on your keyboard. To select a mask,
click it.
c) Create a mask by clicking somewhere in the result display and drawing a line
with the mouse.
One click confirms a line of the mask shape. Add as many lines as you like to
design the mask. A double-click confirms the final shape of the mask.
Using that method, you can design any shape you like around the DUT.
3. Select "Edit Mask" again to exit the editing mode.
Radome Measurements