Antenna technology for the internet in cars

Antenna technology for the internet in cars

Munich, 11. July 2012 – there is no shortage of buzzwords when it comes to the internet in the car. The "car in the cloud" is "always on" or simply "always connected," as automotive supplier delphi calls this "megatrend. Meanwhile, even in many a small car, you can use your smartphone to connect to the internet, for example, to "stream" internet radio, send mails, tweet (must that be?) or maybe actually use services from the cloud.

Internet is even easier with an antenna

One thing is easily overlooked: whether it’s mobile internet, TV or simple radio – if reception doesn’t work, all that’s left of "always online" is chatter or nothing at all. It’s no different today than it was in the good old days of car radios. And a simple rod antenna is no longer enough, there are simply too many different frequencies on which anything is transmitted and received. The egg-laying wool-milk antenna can handle radio and TV, can receive satellite, WLAN, and mobile radio – and all this for different frequency ranges and standards.

Oh well, we don’t need all that – we just put our smartphone in the car and connect it via bluetooth or cable to use it as a UMTS modem. That’s it, but it doesn’t work very well. As gunter bauer from delphi presented at a workshop last week, the range of such a "concept" without an antenna really collapses. In his example – UMTS stick plugged into the center console – the reception radius is only 400 meters. Of course, it’s no better with a smartphone. A stable connection to receive internet radio, for example, is then only possible under good conditions – if the density of wireless towers is high enough and they are not obscured in the tangle of buildings.

Data fin

It is understandable that car manufacturers, especially in the lower segments, shy away from the cost of complex antenna solutions, because they are faced with a dilemma: either they equip cars with a whole mess of antennas, or they develop an integrated solution, which involves technical chin-ups and not entirely low costs. Delphi offers such a solution, which is currently found only on high-end cars. At the rear end of the roof, several antennas are housed in a kind of shark fin; in series production, for example, there is a module that combines GSM 900 and 1800, GPS and SDARS under a small pointed hood. SDARS (satellite digital audio radio services) is a standard for the reception of satellite radio, through which sirius is received in the USA, for example. These antennas can also be placed in other ways, for example in the rear spoiler. But a central position on the roof is the best position for reception, according to delphi.

With the antenna fin, the new reception techniques are covered, but for radio and TV, additional solutions are still required, because they process wavelengths that require their own, coarser antennas, either a rod antenna or antennas that are built into the rear window. In germany and some parts of europe, terrestrial reception will probably continue to play a dominant role, because DVB-T or DAB use a tightly meshed, existing broadcasting infrastructure.

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