Cars Are One of the Most Electromagnetically Demanding Environments
Aug 24, 2026Digital & Product Solutions / AutomotiveOur expert Raúl González, VP Business Line EMC & RF at DEKRA, explains why EMC is critical to modern vehicles, how the challenge has evolved, and why it remains largely invisible to drivers.
In the automotive world, some of the most important engineering aspects are also the ones drivers know the least about. Consumers evaluate a vehicle through aspects they can easily perceive, like acceleration, fuel consumption, range or comfort. However, behind all these functions lies another critical factor that remains largely invisible: electromagnetic compatibility (EMC).
Why is EMC often overlooked by end users? Our expert Raúl González, VP Business Line EMC & RF Testing at DEKRA, explains it: “Automotive EMC goes largely unnoticed because, in the end, from the perspective of the end user, EMC isn't something that a driver can touch, see, or feel, so to speak. You can say, ‘This car accelerates from 0 to 100 km/h in 5 seconds,’ or ‘It consumes 6 liters per 100 km’, for example. But you don't say, ‘This car can withstand driving past a high power electric line or nearby a TV radio station with an electric field of 140 V/m without even flinching.’ You just don't see it.”
This lack of visibility does not mean that EMC is less important. In fact, it is one of the key factors that allows modern vehicles to function reliably despite containing hundreds of electronic systems that must operate simultaneously. A driver may not notice the EMC engineering behind a vehicle during normal operation, but it is what helps ensure that critical systems such as sensors, communication modules, or electronic control units (ECUs) continue working correctly in an increasingly complex electromagnetic environment.
But while EMC may be invisible to drivers, the electromagnetic environment inside a vehicle is far from simple.
The automotive sector is considered one of the most electromagnetically demanding operating environments.
Raúl González, VP Business Line EMC & RF at DEKRA
What’s Interfering With What in My Car?
Modern cars operate in one of the most challenging electromagnetic environments, where multiple sources of interference must be controlled and managed. “The automotive sector is considered one of the most electromagnetically demanding operating environments,” highlights González. “This is because it is characterized by numerous voltage spikes, transient events, and sources of electromagnetic interference.”
Some of these disturbances are inherent to the vehicle itself. Starting an engine, for example, can generate significant voltage transients, while an electrostatic discharge (ESD) can occur when a person enters the vehicle and touches a metal surface after building up static electricity. At the same time, the vehicle’s electrical architecture creates further chances for electromagnetic interaction, since modern vehicles contain extensive wiring harnesses, with large numbers of cables routed closely together throughout the vehicle.
This dense electrical architecture increases the possibility of electromagnetic coupling between different systems, meaning that interference generated by one component can potentially affect another. This is where the two fundamental aspects of EMC come into play: emissions and immunity.
“When you talk about EMC, there are always two fundamental aspects,” he says. “The first is that a device should not generate interference, or at least it should generate as little as possible. The second is that, if a device is exposed to interference, it must be affected as little as possible, because what happens if a piece of equipment malfunctions and starts generating interference? That interference should not cause any of the devices or the whole vehicle to malfunction or fail.”
In other words, a vehicle must both control the electromagnetic energy fields it generates and remain sufficiently robust when exposed to interference from other sources. These two requirements are closely connected. A system that generates excessive interference can affect other electronic components, while a system with insufficient immunity may malfunction when exposed to disturbances generated elsewhere. It can be a simple problem, like a Bluetooth hands-free disconnection or a poor Wi-Fi connection for the vehicle entertainment system, or a high-risk situation for vehicle occupants, such as an airbag explosion while driving or emergency brake deployment due to a wrong detection by ADAS systems.
From Engine Sparks to High-Voltage Batteries
The automotive industry has been dealing with electromagnetic compatibility for decades. However, the nature of the challenge has evolved considerably as vehicles have incorporated more electrical and electronic technologies.
“If you look at automotive EMC a few years ago, the situation was very different,” notes Raúl González. “Thirty or forty years ago, the main concern was voltage spikes and transients generated during engine start-up, since generating the spark needed to ignite the fuel-air mixture required high voltage, creating electromagnetic disturbances that had to be considered. Beyond this, the electrical architecture of a typical vehicle was relatively limited, with only a small number of other electrical systems, such as electric window motors.”
Today, the situation is very different. The rise of advanced driver assistance systems (ADAS), connected vehicle technologies and electrification has accelerated an automotive EMC transformation. “Nowadays, cars are packed with electronics. ECUs and sensors are distributed throughout the vehicle, managing everything from powertrain functions and braking to driver assistance and communications. In electric and hybrid vehicles, the introduction of high-voltage batteries and EV motor inverters adds another layer of electromagnetic complexity, which generates strong electromagnetic fields that can affect nearby systems”, explains González.
However, the fundamental principle of EMC remains the same over time: ensuring that electronic systems can coexist without interfering with one another and can continue to operate correctly when exposed to electromagnetic disturbances. What has changed is the number of systems involved and the complexity of their interactions.
Nowadays, cars are packed with electronics. ECUs and sensors are distributed throughout the vehicle, managing everything from powertrain functions and braking to driver assistance and communications.
Raúl González, VP Business Line EMC & RF at DEKRA
How Cars Became Electromagnetically More Complex?
The increasing number of electronic and wireless systems in modern vehicles has also changed the electromagnetic conditions they need to withstand. As new technologies have been introduced, the frequency ranges considered in EMC testing have had to evolve accordingly.
“At the beginning, for example, a car’s immunity requirements only went up to a frequency range of around 1 GHz, with a test point at 1 GHz,” explains González. “Why? Because at that time, there was a mobile phone operating at 450 MHz and a car key operating at 315/433 MHz. Everything was in lower frequency ranges, so there was no need to test beyond that because there were not many other sources or devices that could interfere with the vehicle”.
The situation began to change as wireless technologies became increasingly integrated into everyday life, and eventually into the vehicle itself.
“Initially, cars introduced Bluetooth hands-free systems, for example, and that already goes above 1 GHz, around 2.4 GHz, and the immunity frequency range was extended up to 3 GHz. Later cars started to have Wi-Fi, which can operate around 5 GHz, so the test range was extended again to reach 6 GHz”, he highlights.
And the frequency range continued to expand.
“The range remained at 6 GHz for many years, but now some manufacturers have already increased that range to 7.125 GHz and beyond, because Wi-Fi is also moving into the 6 GHz band. Besides, vehicles include many other high-frequency devices such as 24 GHz and 77 GHz automotive radars for parking and objects/persons detection, and other systems operating at millimeter-wave frequencies. The vehicle itself contains all these radio systems integrated into its sensors, its ADAS systems, and many other functions. So, Automotive EMC has become increasingly complex, and it keeps becoming more complicated over time,” he explains.
The evolution is therefore not simply about adding more technology to the vehicle. It is about creating an increasingly dense electromagnetic environment in which high-voltage electrical systems, wireless communications, sensors, ADAS functions and other electronic systems must all coexist together.
For the driver, most of this complexity remains invisible. But for manufacturers, every new technology introduces another potential source of interference, and another system that must be protected from it.
This raises the next question: how can manufacturers verify that all these systems will continue to perform as intended when exposed to electromagnetic disturbances? The answer lies in EMC testing.
How do You Test a Car for EMC?
According to Raúl González, “an average user has no idea what tests a car has gone through. There are some tests most people know about, for example, the crash tests with the dummies where they smash the car into something and show that the passenger compartment remains intact. In this case, if the car gets a five-star safety rating from Euro NCAP, everyone immediately knows that means it's among the safest cars available. They don't know what has been done to the car to achieve that level of safety, but at least there's something tangible, a rating system that a non-expert user can interpret, even without any technical knowledge. In the EMC field, there is no equivalent rating system that is easily interpretable by non-experts. However, each vehicle manufacturer has its own validation programs, which require higher severity levels than the minimum regulatory requirements to achieve a higher degree of safety.”
EMC testing takes place at different levels. He explains that “there are two types of tests: the ones carried out on separate components, and then the tests performed on the complete vehicle, once those components are integrated into a complete vehicle. In both cases, testing is carried out inside an EMC chamber”.
At the component level, individual electronic control units, sensors and other modules can be evaluated to determine whether they meet the required emissions and immunity performance. But a vehicle is more than the sum of its components. Once all those systems are connected, installed in their final locations and operating together, new electromagnetic interactions can emerge. This is why testing the complete vehicle is an essential part of the validation process.
“There is a very big difference between what car manufacturers require and what is required by regulations,” he says, “EMC regulations establish a baseline, including the requirements for E-mark type approval, but most manufacturers impose additional EMC requirements to achieve greater confidence in vehicle robustness and performance under a wider range of operating conditions”.
Where are EMC Tests Performed?
Testing the electromagnetic performance of vehicles and their components requires highly specialized facilities. These tests are performed in EMC chambers, but not all chambers are the same: some are anechoic chambers, while others are reverberation chambers.
“Anechoic chambers are visually recognizable by the cones and the ferrites on their walls, which absorb electromagnetic energy. The idea is to simulate an environment with no obstacles, where radiation travels outward without being reflected. So, when I take a measurement or connect equipment to generate interference, I know I am measuring what the equipment is actually emitting, because no reflections come back to distort the measurement,” explains González. “DEKRA has more than 80 anechoic chambers distributed around the world, and more than 20 of them are specifically dedicated to the automotive sector.”
However, reverberation chambers are designed to do precisely the opposite of anechoic chambers. “They are used when we want to generate a very strong electromagnetic field. The walls are metallic, so the signals are reflected, and these reflections can add to or cancel one another. The stirrers, rotating devices that continuously change the field distribution, help the signals add up and concentrate the energy at a given point. This allows us to achieve much stronger fields with less transmitted power.”
Instead of using large power amplifiers to generate these fields directly, reverberation chambers allow us to perform high-level immunity tests much more efficiently. “These chambers are widely used in the automotive sector, where very high electromagnetic field strengths are required for immunity tests,” he states. “DEKRA has three reverberation chambers, located in Korea, Spain, and the US.”
In addition to these EMC chambers, DEKRA has EMC laboratories across three main regions: Asia, Europe, and the US, with facilities in Taiwan, China, Korea, Japan, Vietnam, India, UAE, Italy, Spain, Germany, the Netherlands, Hungary, Brazil, Chile, and the USA.
The Invisible Challenge Isn’t Going Away
The evolution of automotive EMC mirrors the evolution of the vehicle itself. The electromagnetic challenges were already present when vehicles were predominantly mechanical machines. But as cars have become electronic, electrified, connected and increasingly automated, those challenges have multiplied.
“The challenge has always been there, but the car has changed enormously. Not so many decades ago, vehicles had far fewer electronic systems, and the electromagnetic environment was much simpler. Today, we have dozens of systems, wireless technologies, high-voltage systems, sensors and increasingly automated functions all operating together. And this is not going to stop. Cars will continue to become more connected, more automated and more electrified, so the EMC challenge will continue to evolve with them. We will have to make sure that all these technologies can continue to coexist and operate safely and reliably", concludes Raúl González.
For the driver, much of this remains invisible, and it will probably continue to be so. There is no simple EMC rating on a vehicle specification sheet that tells a customer how resilient a car is to electromagnetic interference. But every time a complex electronic system performs exactly as intended despite the electromagnetic disturbances around it, EMC testing and certification are doing their job.
That may be the defining characteristic of automotive EMC: the better it works, the less anyone notices it.