The new features of automotive interiors come at a cost of multiple sets of wireless information and content being delivered transparently to the driver. In the past, this was at most two antennas - AM and FM for the entertainment system. Modern vehicles need a few more antennas, and the count is growing. A typical high-end car today has AM, FM, Satellite Radio, TPM, Remote Entry, Remote Start, In-Vehicle TV, DAB, GPS, Bluetooth, Collision Avoidance Radar, Parking Assist Radar and Electronic Toll Collection. Next-gen vehicles will add GSM and LTE in addition to Wi-Fi, specialized Car-To-Car Communications and additional systems for automated drivers assist. One of the challenges of these systems is directionality of the antenna and its ability to pick up the signal with the vehicle facing different directions. The nominal solution for this issue is the use of a diversity system that employs multiple antennas and then has circuitry to determine which one has the strongest signal, and then use that one. However with the large number of antennas needed in the system - over 15 now and quickly approaching 20 - initial placement of these antennas in a non-interfering manner on the vehicle is a big challenge. This is even before the duplicating of the antennas to support the diversity requirements. The antennas are still passive, but have migrated from Mast/Whip antennas, to glass-mount antennas to the new generation bee sting antenna designs and the shark fin modules. These are being used with a combination of the glass-mount antennas and new distributed antennas. As the frequency diversity increases more shapes of antennas are needed, as shown in the table below (courtesy of Intech):
Posted on: Wed, 02 Oct 2013 18:53:52 +0000
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