Apple: Antenna Design and Test Labs

Every smartphone has a cellular antenna. And nearly every smartphone can lose signal strength if you hold it in a certain way. To make sure our antennas work as well as they possibly can,
 Apple has invested more than $100 million building its advanced labs. Our engineers have logged thousands of hours designing and testing iPhone 4 in these state-of-the-art facilities.

Understanding attenuation and signal loss.

The opposite of amplification, attenuation happens whenever a signal is obstructed. All antennas — including television, radio, GPS, and cellular antennas — can experience attenuation. And with most antennas, the density and composition of the human hand can cause attenuation to a greater degree than some other materials. On a mobile phone, signal loss typically occurs when your hand attenuates the most sensitive part of the antenna. Which, on iPhone 4, is the black strip of the lower left corner of the antenna band.

Apple never releases a product without thoroughly testing it first. To do this, we built our multimillion-dollar antenna design and test labs. These labs feature 17 different antenna characterization chambers (or anechoic chambers) designed to accurately measure antenna and wireless performance.

Testing performance in the lab.

Our anechoic chambers are connected to sophisticated equipment that simulates cellular base stations, Wi-Fi networks, Bluetooth devices — even GPS satellites. These chambers measure performance in free space, in the presence of materials simulating human tissue (“phantom” heads and hands, for example), and in use by human subjects. Over a one- to two-year development cycle, Apple engineers spend thousands of hours performing antenna and wireless testing in the lab.

Testing performance in the field.

Apple engineers tested iPhone 4 in a variety of scenarios, environments, and conditions in order to gauge performance. They spent thousands of hours in cities in the U.S. and throughout the world testing iPhone 4 call quality, dropped-call performance, call origination and termination, and in-service time. They tested iPhone 4 while stationary, at high and low speeds, and in urban, dense urban, and highway environments. In low-coverage areas and good-coverage areas, during peak and off-peak hours — iPhone 4 was field-tested in nearly every possible coverage scenario across different vendor and carrier equipment all over the world.


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