Radiating confidence

These days, electronics such as smartphones, on-board vehicle computers and wireless local area networks are all-pervasiveyet each device emits electromagnetic radiation. At its laboratory in Yonezawa (Japan), TÜV SÜD is testing whether this undesirable side effect might pose a potential danger to humans.


leg 5  ■  houston ➡ yonezawa  ■  11,250 Km  ■  Arrival 13.11.2015, 8:00 a.m.  ■  travel time 75 hrs  ■  15°C  ■  total distance 40,250 KM

Wall know that sound: whenever you hear static and rhythmic beeping on your radio’s speaker, a nearby smartphone has probably just received a text message. This kind of interference used to be a common occurrence, particularly in the early days of cellular phone networks. It would happen whenever two devices—a cell phone and a radio, for example—accessed similar radio frequencies.

It’s annoying when an electrical appliance briefly interrupts your favorite radio broadcast. But some of these disruptions can be dangerous as well. Could, say, a Bluetooth connection cause machines in a hospital intensive care unit to shut down? Can a vehicle’s Brake Assist stop the vehicle abruptly under the influence of public Wi-Fi? And why do you have to turn off your smartphone on airplanes?

Eiji Akiba is not troubled by questions like these—not because he worries less than other people, but for professional reasons. Every day, at TÜV SÜD’s electromagnetic compatibility (EMC) testing laboratory, the largest of its kind in the world, the 38-year-old test engineer works to prevent interference between electronic devices from becoming dangerous.


Wave Absorber

Wave Absorber

In the echo-free chamber, Eiji Akiba tests even whole server racks for their tole-rance to electromagnetic radiation. The room is entirely fitted with special panels—providing complete protection from outside influences.




In Yonezawa, just under three hours by train from Tokyo, Akiba and his colleagues examine computers, cell phones, household appliances and medical equipment, from button-sized Bluetooth sensors to refrigerator-sized servers. In fact, an entire ambulance has already been tested, including all its emergency medical equipment.

In a nutshell, this state-of-the-art testing facility on the outskirts of Yonezawa addresses two simple questions: 1) How much radiation does a device emit? and 2) How well is the device itself protected from radiation? Interference radiation and interference immunity are the technical terms for these properties. In order to draw conclusions, the team led by Eiji Akiba must invest an enormous amount of resources, because it is not only electrical appliances that emit waves. Electromagnetic fields are virtually everywhere: the earth itself and the sun generate them, but radio antennae, transmission stations, wireless routers and pylons do as well. We are constantly being exposed to them.


Testing in a Bank safe

The first order of business at the testing laboratory, therefore, is to seal off the test area from as much of this interference as possible. The three windowless echo-free chambers (the largest of them roughly the size of a school gymnasium) are hidden behind thick concrete walls. In addition, they are padded with special styrofoam that can be relied upon to absorb sound and electromagnetic waves.

Eiji Akiba enters one of the chambers through a steel door reminiscent of a bank vault, nearly 80 centimeters thick. Aside from a small rotary table and a measurement antenna, the room is completely empty. Akiba places a laptop on the table, connects it to a power source and opens the screen. Softly whirring, the computer boots up.


Riding the waves 

With Akiba-san in the echo-free chamber



The measurement antenna stands exactly 10 meters away from the test object. This antenna is not a rigid tube, but a flexible construction with adjustable height and rotation. Naturally, it is fully automated—there is no admittance to the testing facility during an EMC test.

After leaving the testing chamber, Eiji Akiba closes and locks the steel door and launches the test program. Several cameras transmit the test to the control room, allowing Akiba to intervene manually at any time. The table with the laptop slowly rotates clockwise; the measurement antenna systematically moves up and down, back and forth, and makes a 360-degree rotation. In this way, the electromagnetic fields produced by the laptop are recorded from all angles and directions.


Saving time and money

By late afternoon, it is clear that the device is working properly and the electromagnetic radiation is far below prescribed limits. The manufacturer, a Japanese corporation, has cleared an important hurdle to gaining approval for offering the laptop in Europe, America or another target market. The waves transmitted by the computer have no measurable side effect on other devices. Moreover, its own interference immunity is strong enough to shield against potential external radiation.

What if a standard isn’t met? The manufacturer will not be able to put its device on the market unless it has been re-engineered. But such a situation rarely arises. Most companies already have their products tested in the development phase using prototypes, which saves time and money and avoids unpleasant surprises.

Eiji Akiba is well aware that development-related testing has greatly reduced the number of finished products that fail EMC tests. Their interference radiation is constantly decreasing: for some time now, the majority of smartphones, tablets and laptops have been designed so that many airlines allow their in-flight use. They must only remain switched off during critical takeoff and landing phases.