|A sampling of the different antennas used in modern cars|
• AM/FM radio
• Satellite radio
• Digital radio
• WiFi or Bluetooth
• Remote keyless entry
• Embedded cellular phone
• Global positioning system
• DSRC (dedicated short-range communication)
TOKYO -- Not all that long ago, the average car had just one antenna: to handle AM/FM radio.
These days cars are packed with up to seven, handling infrared communications, global positioning, TV, assorted short-range receivers and on-the-go Internet.
And that doesn't include the multitude of wireless sensors used in active safety systems.
Antennas traditionally are unglamorous, low-cost and low-tech parts. But the rush to go wireless has made them a critical, if unsung, necessity for today's high-tech cars.
The shift highlights a big growth sector for suppliers. But it also poses challenges for designers trying to pack the often-unwieldy antennas into a vehicle.
Global automotive antenna sales are expected to surge from $854 million in 2012 to $1.38 billion in 2020, predicts Harada Industries Co., Japan's largest antenna supplier.
Demand is expected to jump in 2015, when the European Union requires new cars to have an emergency 911 service called eCall, similar to General Motors' OnStar system.
The system, which requires antennas for the Global Positioning System and cellphones, is just part of a general proliferation of onboard gadgetry that requires wireless connections with the outside world. Much of it is for infotainment, but it increasingly relates to safety and intelligent transport systems, such as those used to collect tolls, increase fuel efficiency or mitigate congestion.
"Today, the automotive antenna industry is very small," says Tak Aoki, executive officer in charge of corporate affairs at Harada. "But it is important for people's entertainment and, in the future, it will be even more important to their safety."
The global market for wireless technology in cars, including in-cabin Bluetooth and embedded cell phone connections, will climb to $1.6 billion in 2018, from $1.1 billion in 2012, IHS Automotive predicts. Antennas are the necessary link to make them work.
Each communication channel has its own frequency and requires a specially tailored antenna to capture the signal, transmit or to send and receive. Shapes differ: FM antennas are long, thin whips; GPS receivers are flat chips; phones get short stubby masts.
Additional demand for antennas will come from active safety systems that deploy vehicle-to-infrastructure wireless systems, called DSRC, to warn of blind spots or aid in traffic sign recognition. Automakers and suppliers are also developing wireless systems so vehicles can track each other and avoid accidents.
Another demand driver will be remote diagnostics and remote software upgrades. This can be used to aid in spare parts management and alert customers to recalls. Dealerships and off-site mechanics will have to dial in through an antenna to access a car's computer system.
This application typically uses embedded cellular phone connectivity.
About a quarter of U.S. cars sold in 2012 come with this technology, usually as a standard feature, says Luca De Ambroggi, senior infotainment analyst at IHS Automotive.
"OEMs will increasingly want to use embedded cellular for both safety and diagnostic purposes, because the built-in wireless connectivity in cars will prove more robust and reliable than using a tethered or mobile device like a smartphone," he wrote in a July report.
He singled out Kia, Volvo, Daimler and BMW as leaders in embedding cell phones.
Aside from Harada, other major automotive antenna makers include Japan's Yokowa Co., Britain's Laird Technologies Inc., Hirsch-mann Car Communication GmbH of Germany, South Korea's Ace Technology Corp. and Delphi Automotive, through its Fuba division.
Today, many drivers use their mobile phones as a main antenna to the outside world, to make phone calls, listen to Internet radio or use GPS.
But many of those functions will quickly migrate to being installed in the car, predicts SBD, an automotive technology consultancy. Globally, half of all new cars will be fitted with such embedded communications by 2020, compared with around 10 percent today, it predicts.
Uncertain is whether cellphone calls will migrate to embedded antennas. The study said many U.S. mobile carriers are already exploring combined billing for a customer's own smartphone and an embedded cell phone.
Where to pack the antennas is a growing question.
"The antenna needs to communicate with the outside," says Takahiko Uchimura, vice president for strategic planning at ITS Japan, which hosted last year's ITS World Congress in Tokyo in October. "But how it looks is a big issue for designers."
Mounting them on the roof can be unsightly and bad for aerodynamics. Yet they usually have to have a clear line of transmission to the sky, unobstructed by sheet metal.
Indeed, demo cars at the ITS World Congress bristled with antennas like porcupines.
Some antennas can be mounted under the dashboard. That is usually OK because the signal can transmit through the plastic and glass. But being placed too close to the engine can also cause electromagnetic interference and noise that degrades the signal.
Implanting antennas in the A-pillar or along the edge of the roof has the plus of being up high. But that usually requires encasing them in signal-damping metal.
Placing them inside the hollow of side mirrors is another solution.
Yet signal interference again is the enemy -- this time from the motors that adjust the mirror's position or the side blinker lights increasingly fixed to them.
Embedding them in the windshield or rear window is often ideal but also costly. Plus, the reflective qualities of glass in premium cars can also disrupt the signal.
A trendy strategy today is packing different antennas into an aerodynamic casing -- such as the shark-fins used in upscale models -- and mounting that to the roof.
"But it's very expensive," Aoki says of the shark fins.
Antenna makers have to navigate a complicated obstacle course.
They have to juggle signal reception, electromagnetic interference, increasingly complex variety of wireless frequency spectrums and regional differences, De Ambroggi notes.Smart antennas
Engineers are working on so-called smart antennas that can cope, says Rusiru Leelaratne, the chief engineer at Harada's European research center in England.
One approach uses multiple antennas as sort of backups to each other. It allows more data to be transmitted with less interference without gobbling up more bandwidth. But compact packaging is a challenge.
More creative packaging can be achieved through a process known as laser direct structuring, which uses a three-dimensional laser to etch the antenna into molded parts, Leelaratne said.
This gives greater flexibility in form and placement. The technique is proven in mobile phones. But the hurdle is reducing costs for autos, he said.
Packaging these next-generation antennas together could have cost advantages. IHS's De Ambroggi estimates that mounting them together in an "antenna box" on the car roof would save carmakers $30 per vehicle by reducing the use of coaxial cables.
"Some people call this a smart antenna," Leelaratne said. "Integrating two antennas with the receiver next to the antenna is the holy grail of antenna design."