14
Mounting Requirements
Cover Material Requirements
Any material that may be located in the Forward Looking Radar’s
fi
eld of view (including bumpers, spoilers, etc.) can not be made out
of any metallic material or have any carbon content. It is recommended that any material that will be located in the FLR
fi
eld of view be
approved by Bendix Commercial Vehicle Systems prior to use.
If the radar has a cover perpendicular to the radar beam, even a very slight vibration of the cover can cause the re
fl
ected radar signal to be
seen as a very strong false target at close range. If the radar cover is not perpendicular by more than 5° then the returned re
fl
ection does
not enter the receiver channel and hence is not detected. The recommended angle of the beam to the cover is 50° to 80°. There have
been applications that have the cover perpendicular, but the forward radar and the cover were directly mounted to each other to minimize
the cover’s movement to the radar module. This may be a dif
fi
cult condition to maintain.
The cover must not contain any metal or high carbon concentrations, as this reduces the radar range. The electrical characteristics of
the cover material (on microwave RF) and its thickness can effect the range as well. Polymeric or ceramic material is recommended.
Recommended thickness are based on the cover’s angle. The table on the following page lists material thicknesses for a perpendicular or
80° angle cover. The ideal thickness also depends on the angle of incidence of the cover relative to the radar beam axis. The materials in
this table do not represent the only possible make up for a cover.
The recommendation scoring system has been applied as follows:
•
Losses shall be less than 0.7dB.
•
Thickness for rigidity reasons shall be greater than 2mm.
Thickness accuracy: +/- 0.15mm
Thickness recommendation is based on cover being a
fl
at unpainted surface that extends beyond the “No Radar Obstruction Zone” (see
previous page). Since paints can impact the losses, they need to be evaluated separately. As with the cover, the paint must not contain
metal or carbon.
•
The thickness depends on the angle of incidence of the bumper shield located in the radar
fi
eld view relative to the radar beam
axis; it should be updated with the real angle.
•
The angle of incidence is recommended to be between 50° to 80°; 90° is prohibited so as to avoid any spurious re
fl
ection of the
radar beam back into the Forward Looking Radar.
•
Painting can induce extra losses that depend heavily on the painting thickness itself and on its painting process. These paints
need to be tested individually to assess their impact on the recommendations made in this document. For more information, see
the “Painting” section of this publication.
Radar
Beam
Reflected
Beam
Radar
Beam
