Mobile phone commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion—enough to provide one for every person on Earth. In first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple, and Huawei, with smartphone sales represented 78 percent of total mobile phone sales. For feature phones (or "dumbphones") , the largest were Samsung, Nokia, and Alcatel. A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone".
Mobile phone had found no convincing evidence for other health effects. However, a study published 24 March 2012, in the "British Medical Journal" questioned these estimates because the increase in brain cancers has not paralleled the increase in mobile phone use. Certain countries, including France, have warned against the use of mobile phones by minors in particular, due to health risk uncertainties. Mobile pollution by transmitting electromagnetic waves can be decreased up to 90% by adopting the circuit as designed in mobile phone and mobile exchange. In May 2016, preliminary findings of a long-term study by the U.S. government suggested that radio-frequency