The history of Wireless Communications started with the understanding or magnetic and electric properties observed during the early days by the Chinese, Greek and Roman cultures and experiments carried out in the 17th and 18th centuries. Here are some selected events in the development of Wireless Communications (material taken from the book History of Wireless, Tapan Sarkar, et al., Wiley, 2006).

1807 – French mathematician Jean Baptiste Joseph Fourier discovered Fourier’s theorem

1820 – Danish physicist Hans Christian Orsted discovered the electromagnetic field caused by electric current. The French physicist Dominique Francois Jean Arago showed that a wire became a magnet when current flowed through it. French mathematician and physicist Andre-Marie Ampere discovered electrodynamics and proposed an Electromagnetic Telegraph.

1831 – British scientist Michael Faraday discovered electromagnetic induction and predicted existence of electromagnetic waves.

1834 – American inventor Samuel Finley Breese Morse invented the code for telegraphy named after him.

1847 – German physiologist and physicist Hermann Ludwig Ferdinand von Helmholtz suggested electrical oscillation

1853 – William Thomson (Lord Kelvin) calculated the period, damping and intensity as a function of the capacity, self-inductance and resistance of an oscillatory circuit.

1857 – Feddersen verified experimentally the resonant frequency of a tuned circuit as suggested by Helmholtz in 1847.

Maxwell1864 – Scottish mathematician and physicist James Clerk Maxwell formulated the electromagnetic theory of light and developed the general equations of the electromagnetic field. He formulated 20 equations that were later simplified into the 4 basic equations we use today.

1866 - American dentist Dr. Mahlon Loomis described and demonstrated a wireless transmission system which he patented in 1866. Loomis demonstrated the transmission of signals between two mountains, a distance of 22 km.

1882 – American physicist, Amos Emerson Dolbear, was granted a patent for a wireless transmission system using an induction coil, microphone and telephone receiver and battery. Nathan Stubblefield transmitted audio signals without wires.

1883 – Irish physicist and chemist George Francis FitzGerald published a formula for the power radiated by a small loop antenna.

1884 – German physicist Heinrich Rudolf Hertz wrote Maxwell’s equations in scalar form by discarding the concept of aether reducing it from 20 to 12 equations.

1885 – Thomas Edison patented a system of wireless communication by electrostatic induction.

1886 – Heaviside introduced impedance as the ratio of voltage over current. Hertz started his work to demonstrate the existence of radio waves and published his results in 1888.

1887 – English physicist Oliver Joseph Lodge discovered Sympathetic Resonance (standing waves) in wires.

1888 – Hertz produced, transmitted, and received electromagnetic waves (5 m to 50 cm) using reflectors to concentrate the beam.  Hertz also discovered the principle for Radar. Heaviside wrote Maxwell’s equations in vector form – the four equations we use today. Italian Galileo Farrari and Croatian-American Nilola Tesla independently produced rotating fields using 2-phase currents. Austrian engineer Ernst Lecher established the relation between frequency, wire length, velocity of propagation and the electrical constants of the wire.

1890 – Lecher used standing waves produced in parallel wires to measure frequency. Tesla introduced high frequency currents in therapeutics as he observed that current of high frequency could raise the temperature of living tissue. Tesla also patented his Tesla Coil which was used later in every spark gap generator to produce high frequency signals. Heinrich Rubens and R. Titter made a sensitive bolometer which measured the intensity of electromagnetic waves by means of the heat generated in a thin wire.

1893 – English physicist Joseph John Thomson published the first theoretical analysis of electric oscillations within a conducting cylindrical cavity of finite length suggesting the possibility of wave propagation in hollow pipes (waveguides). Hertz conducted experiments of EM shielding and for coaxial configuration.

Marconi1895 – Marconi transmitted and received a coded message at a distance of 1.75 miles near his home in Bologna, Italy. Indian physicist, Sir Jagadis Chunder Bose generated and detected wireless signals and produced many devices such as waveguides, horn antennas, microwave reflectors and more.

1897 – Marconi demonstrated a radio transmission to a tugboat over an 18 mile path over the English Channel. The first wireless company, Wireless Telegraph and Signal Company was founded – they bought most of Marconi’s patents. Lord Rayleigh suggests EM wave propagation in waveguides and analysis of propagation through dielectrically filled waveguides. Lodge patented various types of antennas.

1899 – Marconi sent the first international wireless message from Dover, England to Wimereux, France.

1900 – Tesla obtained patents on System of Transmission of Electrical Energy which the US recognized as the first patents on Radio. Tesla is the first person to describe a system of determining the location of an object using radio waves – Radar.

1902 – Fessenden patented the Heterodyne receiver. American Cornelius D. Ehret filed patents covering the transmission and reception of coded signals or speech (Frequency Modulation – FM). Poulsen was the first to develop the CW transmitter.

1903 – Marconi established a transmission station in South Wellfleet, MA – the dedication included exchanges of greetings between American President Theodore Roosevelt and British King Edward VII. G.

1904 – Frank J. Sprague developed the idea of the printed circuit. W. Pickard filed a patent application for a crystal detector where a thin wire was in contact with silicon. It was the central component in early radio receivers called crystal radios.  J. C. Bose was granted a patent on point contact diodes that were used for many years as detectors in the industry.  Fleming suggested the rectifying action of the vacuum-tube diode for detecting high frequency oscillation – the first practical radio tube.

1905 – Fessenden invented the superheterodyne circuit.

1906 – Lee de Forest patented the general principle of omni-range using a rotating radio beam keyed to identify the sector forming 360 degree sweep of the beam. He also invented the three-electrode valve or vacuum tube triode that was instrumental in the development of transcontinental telephony in 1913. Poulsen transmitted music by wireless using an arc transmitter with 1 kW of input power and a 200 feet high antenna that was heard 300 miles away.

1909 – Marconi and Braun shared the Nobel Prize for Physics for their contributions to the physics of electric oscillations and radiotelegraphy.

1911 – Von Lieben and Eugen Riesz developed a cascade amplifier. Hugo Germsback, an American novelist, envisaged the concept of pulse radar in one of his works where he proposed the use of a pulsating polarized wave, the reflection of which was detected by an actinoscope.

1911 – Engineers start to realize that the triode can also be used for transmitter and oscillator – the three-electrode vacuum tube was included in designs for telephone repeaters in several countries.

1912 – G. A. Campbell developed guided wave filters. Sinding and Larsen transmitted TV by wireless using 3 channels. The Institute of Radio Engineers was formed in the US.

1914 – The German physicist Walter Schottky discovered the effect of electric field on the rate of electron emission from thermionic-emitters named after him. Fleming discovered the atmospheric refraction and its importance in the transmission of EM waves around the Earth. Carl R. Englund was the first to develop the equation of a modulated wave (AM) and also discovered the frequencies related to sidebands. Frequency modulation of a carrier was proposed to accommodate more channels within the available bandwidths.

1915 – Schottky stated work on the space-charge-grid tube and a screen grid tube or Tetrode that achieved good amplification by placing a screen grid between the grid and the anode.

1916 – Leon m Brillouin and Georges A. Beauvais patented the R-C coupled amplifier. F. Adcock used open vertically spaced aerials for direction finding in aircraft and granted British patent.

1918 – Armstrong invented the Superheterodyne Radio Receiver using 8 valves – most receivers still use this design today. Langmuir patented the feedback amplifier. E. H. O Shaughnessy development of direction finding was one of the key weapons in England during WWI – Bellini-Tosi aerials were installed around the coast to locate transmission from ships and aircrafts. Louis Alan Hazeltime invented the neutrodyne circuit with tuned RF amplifier with neutralization.

1919 – Marconi-Osram company developed the U-5 twin-anode full-wave rectifier. Joseph Slepian filed a patent application for a vacuum tube electron multiplier. Sir Robert Alexander Watson-Watt patented a device for radiolocation by means of short-wave radio waves – the forerunner of the Radar system.

1921 - E. S. Purington made the all-electric frequency modulator. A.W. Hull invented the Magnetron oscillator operating at 30 kHz and output power of 8 kW and 69 percent efficiency. E. H. Colpitt and O. B. Blackwell developed modulation of an audio frequency carrier by signals of lower audio frequency for carrying telephony over wires. S. Butterworth published a classic paper on HF resistance of single coil considering skin and proximity effect.

1922 – Walter Guiton Cady invented the piezoelectric (Quartz) crystal oscillator. The BBC broadcasts is first news program.

1923 – The decibel (1/10th of a bel, after A. G. Bell, inventor of the telephone) was used to express the loss in a telephone cable. H. W. Nichols developed point-to-point communication using single side-band communication. D.C Prince analyzed Class A and Class C amplifiers. Scottish engineer Antoine Logie Barid built and patented the first practical TV. Watson-Watt perfected the radiolocation device by displaying radio information on a cathode ray oscilloscope telling the radar operator the direction, distance and velocity of the target. Ralph Vinton Lyon Hartley showed that the amount of information that can be transmitted at a given time is proportional to the bandwidth of the communication channel. H. Flurschein filed a patent on radio warning system for use on vehicles.

1924 – J.R. Carson showed that energy absorbed by a receiver is directly proportional to its bandwidth and extended Lorentz’s reciprocity theory to EM fields to antenna terminals.  Lloyd Espenschied invented the first radio altimeter.  The mobile telephone was invented by Bell Telephone Company and introduced to NYC police cars.

1925 – First conference on frequency allocation was held in Geneva. Joseph Tykocinski-Tykociner demonstrated that the characteristics of a full size antenna can be replaced with sufficient accuracy from measurements made on a small short wave in the rage of 3 to 6 m.

1926 – L.E. Lilienfield patented the theory of the Field-Effect Transistor. Japanese engineers Hidetsugu Yagi and Shintaro Uda developed the Yagi antenna, a row of aerials consisting of one active antenna and twenty undriven members as a wave canal. Hulsenback and Company patented identification of buried objects using CW radar.

1927 – R. V. Hartley developed the mathematical theory of communications. Harold Stephen Black of Bell Laboratories conceived the negative feedback amplifier. A. de Hass studied fading and independently developed diversity reception system.

1928 – Baird conducted the first transatlantic TV broadcast and built the first color TV. Nyquist published a classic paper on the theory of signal transmission in telegraphy. He developed the criteria for the correct reception of telegraph signals transmitted over dispersive channels in the absence of noise. C.S. Franklin patented the coaxial cable in England to be used as an antenna feeder.

1929 – L. Cohen proposed circuit tuning by wave resonance (resonant transmission line) and its application to radio reception. H.A. Affel and L. Espenscheid of AT&T/Bell Labs created the concept of coaxial cable for a FDMA multi-channel telephony system. K. Okabe made a breakthrough in cm-waves when operating his slotted-anode magnetron (5.35 GHz). Hans Erich Hollmann patented the idea of a reflex klystron with his double-grid retarding-field tube. W.H. Martin proposed the Decibel as a transmission unit.

1931 – H. diamond and F. W. Dunmore conceived a radio beacon and receiving system for blind landing of aircraft. H. E. Hollmann built and operated the first decimeter transmitter and receiver at the Heinrich Hertz Institute. He called the device the magnetron.

1932 – The word Telecommunication was coined and the International Telecommunications Union (ITU) was formed. George C. Southworth and J. F. Hargreaves developed the circular waveguide. Karl Jansky accidentally discovered radio noise coming from outer space giving birth to radio astronomy. R. Darbord developed the UHF Antenna with parabolic reflector.

1933 – Armstrong demonstrated Frequency Modulation (FM) and proposed FM radio in 1936. C.E. Cleeton and N. H. Williams made a 30 GHZ CW oscillator using a split-anode magnetron.

1934 – The Federal Communications Commission (FTC) was created in the US. W.L. Everitt obtained the optimum operating conditions for Class C amplifiers. F. E. Terman demonstrated a transmission line as a resonant circuit. German physicist Oskar Ernst Heil applied for a patent on technology relating electrical amplifiers and other control arrangements that was the theoretical invention of capacitive current control in FETs.

1935 – C. J. Frank of Boonton Radio Corp demonstrated Q-meter at the fall meeting of IRE – the ratio of reactance to resistance of a coil as its “Quality Factor” was first suggested about 1926. A French TV transmitter was installed on top of the Eiffel Tower. Watson-Watt developed and patented the first practical radar for use in the detection of airplanes in England. H. E. Hollmann filed a patent for the multi-cavity magnetron (granted in 1938).

1936 – H. W. Doherty developed a new high efficiency power amplifier for modulated waves, Doherty amplifier, at Bell Labs. English engineer Paul Eisler devised the Printed Circuit. N. H. Jack patented the semi-rigid coaxial cable using thin soft copper tube as the outer conductor. Harold Wheeler used two flat copper strips side by side to make a low loss transmission line that could be rolled to save space. H. T. Friis and A. C. Beck invented the horn reflector antenna with dual polarization.

1937 – Grote Rober constructed the first radio telescope. W. R. Blair patented the first anti-aircraft fire control radar. Russell H. Varian and his brother Sigurd Varian along with William Hansen developed the reflex Klystron. Alex H. Reeves invented pulse-code modulation for digital encoding of speech signals.

1938 – E. L. Chaffee determined the optimum load for Class B amplifiers. IRE published standards on transmitters, receivers and antennas. Claude Elwood Shannon recognized the parallels between Boolean algebra and the functioning of electrical switching systems. W. R. Hewlett developed the Wien-bridge (RC) oscillator. P. H Smith at RCA developed the well known Smith Chart. N. E. Lindenblad of RCA developed a coaxial horn antenna. John Turton Randall and Albert Boot developed the cavity magnetron that becomes the central components to radar systems.

1941 – W. C. Godwin developed the direct-coupled push-pull amplifier with inverse feedback. Siemens & Halske made the Ge diode – R. S. Ohl made the Si junction diode. Sidney Warner realized a two-way police FM radio.

1943 – H. J. Finden developed the frequency synthesizer. Austrian engineer Rudolf Kompfner developed the traveling wave tube. C. K. Chang developed frequency modulation of RC oscillators. C. F. Edwards developed microwave mixers.  H. T. Friis developed noise figures of radio receivers.

1944 – Harold Goldberg suggested pulse frequency position modulation. E. C Quackenbush of Amphenol developed the VHF coaxial connectors. Paul Neil of Bell Labs developed Type N connectors. Maurice Deloraine, P. R. Adams and D. H. Ranson applied for patents covering switching by pulse displacement a principle later defined as time-slot interchange – Thus, Time-Division Multiplexing (TDMA) was invented. Radio Research Lab developed radar countermeasures (jamming) in the 25 MHz to 6 GHz range.

1946 – S. L. Ackerman and G. Rappaport developed a radio control systems for guided missiles. E. M. Williams developed the radio frequency spectrum analyzer.

1947 – G. E. Mueller and W. A. Tyrrel developed the dielectric rod antenna. John D. Kraus invented the helical antenna. W. Tyrell proposed hybrid circuits for microwaves, H. E. Kallaman constructed the VSWR indictor meter.

1948 – W. H. Branttain, J. Bardeen and W. Shockley of Bell Labs built the junction transistor. E. L. Ginzton and others developed distributed wideband amplifier using pentodes in parallel. Shannon laid out the theoretical foundations of digital communications in a paper entitled “A Mathematical Theory of Communication.” Paine described the BALUN.

1949 – E. J. Barlow published the principle of operation of Doppler Radar.

1950- J. M. Janssen developed the sampling oscilloscope.

1951- Charles Hard Townes published the principle of the MASER (Microwave Amplification by Stimulated Emission of Radiation).  The Laboratoire Central des Telecommunications in Paris developed the first model of a time-division multiplex system connecting subscriber line by electronic gates handling amplitude modulated pulses.

1952 – C. L. Hogan demonstrated a microwave circulator.

1955 – R. H. DuHamel and D. E. IsBelll develop the log periodic antenna. John R. Pierce proposed using satellites for communications. Sony marketed the first transistor radio.

1957 – Soviet Union launched Sputnik I that transmitted telemetry signals for about 5 months. German physicist Herbert Kroemer originated the concept of the heterostructure bipolar transistor (HBT).

1958 – Robert Noyce (Intel) and Jack Kilby (TI) produced the first Si integrated circuit (IC).

1962 – G. Robert-Pierre Marie patented the wide band slot antenna. S. R. Hofstein and F. P. Heiman developed MOS IC.

1963 – W. S. Mortley and J. H. Rowen developed surface acoustic wave (SAW) devices. John B. Gunn of IBM demonstrated microwave oscillations in GaAs and InP diodes. The Institute of Electrical and Electronic Engineers (IEEE) was formed by merging the IRE and AIEE.

1964 – R. L. Johnson, B. C. De Loach and B. G. Cohen developed the IMPATT diode oscillator. COMSAT and INTELSAT started launching a series of communications satellites that were the building blocks in the global network of international communications satellites.

1969 – The first digital radio-relay system went into operation in Japan using 2 GHz operating frequency. ARPANET was launched (precursor to Internet).

1971 – Statek began manufacturing and marketing quartz oscillators that were made using their patented photolithographic process.

1978 – AT&T Bell Labs started testing a mobile telephone system based on cells.

1980 – CW performance of GaAs MESFET reached 10 W at 10 GHz. ATLAS I EM pulse simulator was built for testing large aircraft – it was the largest wooden structure in the world (400 x 105 x 75 m).

1989 – F. Laleari invented the broadband notch antenna

1990 – WWW was developed