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.