TE - White Papers

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)

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