TE Connectivity White Paper /// V2X - An important building block in Cooperative Intelligent Transport Systems (C-ITS) Page 8
V2X – An important building block in
Cooperative Intelligent Transport Systems (C-ITS)
directions surrounding the vehicle.
For these reasons most vehicle types
will require multi antenna systems.
Additional system margins must be
reserved for temporary modules like
roof racks or trailers.
4. TE product overview V2X
4.1. Antennas for cars
As shown in figure 11, typical mount-
ing areas for two antennas (antenna
diversity) are either on the vehicle's
left and right or at the front and rear.
Often directional antennas are used
to ensure optimum antenna decou-
pling. This is especially important
for antenna positions at the left and
right side of the vehicle. But front
antennas, too, are mostly direction-
al, thus requiring special compen-
sation.
This compensation refers to the in-
fluence of the windscreen, as this an-
tenna often is mounted behind the
windscreen (see figure 13 (a) antenna
mounted in mirror base).
As the windscreen itself is mount-
ed at a strongly tilted angle and as
the frequencies used are very high,
lensing effects may occur, which the
antenna then must compensate (see
figure 13 (b) Antenna diagram sub-
ject to windscreen influence). The
rear antenna usually is just a "sim-
ple" antenna, without special com-
pensation or directivity, mounted as
part of either the shark fin antenna
system or an integrated antenna sys-
tem.
The integration of a 5.9 GHz antenna
in such an antenna system, togeth-
er with the roof curvature and, for
example, a glass roof, usually cause
preferred emittance towards the ve-
hicle's rear, which ensures good de-
coupling of rear and front antenna.
Fig. 11: Typical V2X antenna mounting areas in a car
Fig. 13: (a) Antennas mounted in inner mirror base; (b) Directional diagram of a V2X antenna subject to windscreen influence
Fig. 12: Different radiation diagrams
of 5.9 GHz antennas and the expected
minimum antenna gain (in yellow)