A brief history of wireless technology

Farpoint Group –

I occasionally end seminars that I conduct on various wireless topics by saying, "Show me another area of high tech, especially one this old, where there's this much innovation going on - I don't think you can." But just how old is wireless technology, anyway? Most people are surprised to find that it goes back well over 200 years.

If we ignore optics, which fascinated early scientists over two thousand years ago, one might argue that the long trail of innovations that have brought us to the fast, cheap, and (mostly) reliable wireless products and services of today in fact began with Benjamin Franklin and his famous kite. It is very unlikely that Franklin actually conducted the experiment as it is often described, with keys tied to a kite string - had he done so, he might never have survived to sign the Declaration of Independence! But Franklin did, in 1747, propose a model of electricity that proved surprising correct. And at that point it was evident that electricity could in fact move through the air.

In 1819, the Danish physicist Hans Christian Oersted noted that a compass needle would move in the presence of an electric field, thus establishing the fundamental relationship between electricity and magnetism. We call the entire field electromagnetics to this day.

In 1831, Michael Faraday demonstrated electromagnetic induction and built the first direct-current generator. While this wasn't useful for wireless communications, it did provide a way to generate electricity.

The next big leap forward was the result of theoretical work by James Clerk Maxwell, the great Scottish physicist. He published "On a Dynamical Theory of the Electromagnetic Field" in 1865, and in 1873 "A Treatise on Electricity and Magnetism," which became what are known Maxwell's Equations. These are a series of very difficult differential equations which describe the movement of electromagnetic waves through space. Remarkably, we use them to this day. I'm always amazed that someone working in a cold, damp building in Scotland, with little in the way of computational technology and probably nothing more than an oil lamp for light, devised something so fundamental and powerful that we still use it. Maxwell, by the way, had never seen a radio; they did not exist then, and he had no actual experience with radio waves themselves. But the theory he developed paved the way for the next set of critical inventions.

Building on Maxwell's work, Heinrich Hertz in 1887 invented the oscillator (an alternating-current generator) and created radio waves. By the way, this is the Hertz of megahertz and gigahertz, not the rental-car company. I should also note that Oersted, Faraday, and Maxwell all had units of physical measurement named in their honor as well.

Now, who exactly should get the credit for the radio is still a subject of debate. Many believe it was in fact Nikola Tesla who first sent information through the air. However, I've never seen evidence that Tesla really communicated something of value - he just moved energy between two points without wire, demonstrating electromagnetic induction. The credit for the radio itself belongs, I think, to Guglielmo Marconi, who in 1895 sent a radio telegraph transmission across the English Channel, and in 1901 a transmission across the Atlantic. Public use of radio began in 1907. By the way, no physical unit was named for Marconi, but he did win the Nobel Prize in 1909 - not bad for a self-taught inventor!

There have been so many great contributions since then, from Edwin Armstrong (who created FM radio, among others), to Lee De Forest (who invented the electron tube), and Andrew Viterbi (who came up with digital decoding and CDMA) - and so many more that we can't list them all here. There are now more people working in wireless communications than at any other time in history. So as the computer industry suffers, to some degree, from the pains of maturity, wireless shows no such trend towards slowing down.

"If I have seen further it is by standing on ye shoulders of Giants," Isaac Newton wrote that in a famous letter of his to Robert Hooke, the great English scientist and inventor. Today, after well over 200 years, we continue to build on the work of an amazing number of inspiring people who were fascinated with the concept of communication through the air. And the innovations, as regular readers of this column can attest, continue at a remarkable pace.

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