Arthur E. Kennelly
Arthur E. KennellyBorn: 17 December 1861
Died: 18 June 1939
In 1901, Kennelly noticed that Guglielmo Marconi’s reception in Newfoundland of radio signals transmitted from England was received far better than predicted by radio-wave theory. Kennelly and the Englishman Oliver Heaviside, independently, and at approximately the same time in 1902, announced the probable existence of a layer of ionized gas high in the atmosphere that reflected radio waves. Formerly called the Heaviside or Kennelly-Heaviside layer (now called the E region), it is one of the several layers of the ionosphere. Although short wavelength radio waves penetrate the ionosphere, longer waves reflect off it instead, a property which allows them to “curve” around the earth and be propagate far beyond the horizon.
Kennelly is also known for the contributions he made to the analysis of alternating-current (AC) circuits with the publication of his paper “Impedance.” In that paper he described the first use of complex numbers as applied to Ohm's Law in AC circuit theory.
Kennelly received many awards during his lifetime. These included the IEE Institution Premium, the Franklin Institute Howard Potts Gold Medal, the Cross of a Chevalier of the Legion d'Honneur of France, and the AIEE Edison Medal. Kennelly died in Boston, Massachusetts on 18 June 1939.