Why antennas are the workhorse of the connected car (Reality Check)
Connected cars are gathering steam as automakers not only need to provide the latest in infotainment technologies, but also deliver a wealth of useful vehicle data to automobile owners. But these new capabilities come with a new set of challenges — with all the additional antennas required to deliver the breadth of today’s connected car capabilities, where and how do you put them in a vehicle and still optimize cost, size, installation flexibility and performance?
There are simply too many antennas to all fit into the “fin” on the exterior of the vehicle. However, vehicle chassis and pillars have evolved from all metal to a mix of more RF-friendly materials. This means antennas can be placed virtually anywhere in the vehicle—underneath the roof, in the A or B pillars, inside a side mirror, trunk or bumper, or even under the dashboard. But making that happen in a coordinated way, keeping high performance, without interference, and meeting the mechanical specifications for many antennas, is creating challenges.
Antennas play a critical role not only in today’s connected car, but in those of the future as well. Connected cars require high-speed internet connections for several reasons today, such as eCall, vehicle diagnostics and for vehicle manufacturers to push software updates to the car. Autonomous vehicles will take that connectivity requirement to a whole new level; regardless of whether they are in a metro area or in a remote area, they need consistent access to high-speed reliable low latency to be able to deliver autonomous driving, and safety-critical applications such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I), and data collection for artificial intelligence (AI).
As a group, they can’t just be “good enough”—they have to work flawlessly and seamlessly in combination to deliver on performance and safety. Anything less, and very literally lives are at risk.
Key placement considerations
There is no single answer about the best place for the different antennas within the vehicle, because each vehicle design calls for a different antenna layout, increasing the challenge not only for vehicle manufacturers, but for antenna manufacturers as well in terms of design and engineering choices. Luxury and higher-end cars obviously do not compromise on performance or by “leaving something out.” Expectations have greatly increased in all vehicles, and even the cheaper small cars and vans offer some of the latest technologies as standard—and antenna vendors are expected to deliver at a fraction of the usual cost. There is no one-size-fits-all solution that works for every manufacturer.
One of the biggest challenges brought on by the wealth of placement options is the time it takes to order and test different antenna solutions for placement, proximity, size and other factors, and how these characteristics impact performance. Custom solutions can take months, severely delaying the ability of manufacturers to bring new capabilities and the very latest technologies to their latest models. Antenna vendors are now beginning to bring to market sample reference antenna designs for connected car solutions for 2022 and beyond, so a car in 2022 does not enjoy the advancements of 2020 and 2021.
There are several other factors to consider when installing antennas for the connected car, including:
- Now that antennas are being brought inside the vehicle, size matters just as much as with exterior antennas, and perhaps even more so. There are three or four antennas inside the traditional fin antenna. The fin size cannot grow, but more antennas are required. Along the same lines, vehicle manufacturers are also looking to reduce the amount of cabling as well to cut down on installation complexity and cost as well as potential vibrations. Both factors indicate that many antennas will be in close proximity to each other and to the actual communication electronics.
- EMC and frequency interference. Antenna manufacturers are working on various methods to reduce interference and help these antennas coexist, including unique design elements and manufacturing methods. In addition, shielding and filtering are being employed as well as software enhancements to handle instances of interference, e.g., GPS multipath or jamming.
- Harsh conditions. Given the ongoing long-term quality requirements auto manufacturers need to meet, antennas must perform in some of the world’s harshest conditions, including:
- Temperatures inside and outside vehicles can reach upwards of 150 degrees Fahrenheit on warm days, and antennas need to be able to take the heat, so to speak. Antenna manufacturers are constantly experimenting with formulas for materials used in antennas to continue to improve performance. An antenna that is close to melting in Arizona in winter can be so brittle in winter in Northern Canada that even a bird hitting the vehicle can smash an antenna enclosure easily.
- Noise and vibration. Speed, bumpy roads, engine noise and other characteristics of moving vehicles can cause noise and vibrations that impact performance. High rates of speed can also create difficulties in receiving/transmitting signals. On PCB surface-mount antennas are emerging as a practical way to deal with the vibration issues.
- Ease of installation. Vehicle assembly is automated, so any antenna installation work must be able to be completed by a robot for quality assurance and to keep costs in check. In many scenarios, antenna solutions need to be able to be mounted during the communication PCB’s reflow process at the Tier 1, hence SMT-mounted antenna and RF components are placed directly onto the board of their telematics control units (thus reducing required cabling).
Auto manufacturers and Tier 1 suppliers are moving forward quickly with their plans to bring increasingly connected vehicles to market. Antennas play a critical role in the future and success of the connected car and help dictate timelines for bringing advanced functionality to market. By working with vehicle manufacturers to overcome the challenges associated with antenna design and placement in a connected car environment, antenna manufacturers are well poised to be a key stakeholder in the next generation of connected vehicles.