There are so many things we have to take into consideration when buying a smartphone: How big and brilliant is the screen? How good is the camera? Does it have the latest software? These are only a few of the questions we ask before taking on a new cellphone.
Thankfully, when buying a Nokia handset, we don’t need to add ‘Does the antenna work properly?’ to that ever-growing list of variables. That’s because guys like Randy Leenerts who is part of the Nokia antenna test team spend over 150 hours on each model painstakingly making sure it does.
Mobile phone = radio
“To me the mobile phone is just a radio,” explains Randy, who works out of Nokia’s lab in Dallas, Texas. “We’re just looking at the transmitter and how well it will transmit the signal to the base station. We also measure the sensitivity of the receiver and how well it can hear the base station. That’s it.”
“If it doesn’t do those two things well enough to pass our tests, it doesn’t go to market, it’s that simple. There can be no such thing as a phone that fails.”
The testing chamber
The main piece of equipment used in the certification process is called a giant space age contraption called an Anechoic Chamber. It’s one of the quietest places on earth, but in this case, silence really is golden.
“It’s a huge metal box that keeps out all of the radio waves,” explains the seasoned Nokia electrical engineer. “On the inside it has cone-shaped absorbers filled with carbon to catch radio waves. Because there are no reflections in the room, it accurately simulates being outside with no objects around the user.”
The phone is placed on a turntable and the device is rotated to form a 3D pattern. The results of that test are averaged out to provide Total Radiated Power and Total Isotropic Sensitivity scores – these numbers represent the pass and fail criteria.
Other tests involve a phantom head, complete with brain fluid, and phantom hands, which simulate different grips to ensure the antenna still performs effectively and keeps dropped calls to a bare minimum.
The important final step
By the time the device reaches the antenna test lab the smartphone is almost complete. The antenna has already been designed, positioned and implemented within the finished device in the development labs. “It’s too late to make any design changes,” Randy says. For everyone who worked on the phone, his certification process is a final step before it can be placed in the hands of consumers. But what’s the big deal? Isn’t it just a formality?
“Ten or 15 years ago, we had single band GSM phones with antennas outside the device and they worked really well,” Randy explains. “The reason that this test exists today is because they’ve been brought inside the phone, have become much more complicated and so making them work effectively is a much larger challenge.
“It’s not just the one antenna anymore. There’s GPS, Wi-Fi, Bluetooth, low-band, high-band and they all have to work together and, at the same time, kept very small to fit within the device.
Metal is an antenna nightmare
“People love their shiny metal-backed covers, but that’s very bad for antennas. Putting antennas behind plastic covers is also a big challenge. Depending on where the users put their fingers, the positioning of the antenna can also have a huge effect on performance.”
Doesn’t sound so straightforward anymore, does it?
So, next time you make a call on your Nokia Lumia 900, spare a thought for Randy and the 150 hours this Nokia test team spends ensuring that a potentially life-changing conversation will not disappear into the abyss thanks to an untimely dropped call. His tests are a small, but hugely crucial part of putting your favorite smartphone in your hand.