Jonathan Adolf Wilhelm Zenneck (15 April 1871 – 8 April 1959) was a physicist and electrical engineer. Zenneck was born in Ruppertshofen, Württemberg. Zenneck contributed to researches in radio circuit performance and to the scientific and educational contributions to the literature of the pioneer radio art. Zenneck improved the Braun cathode ray tube, by adding a second deflection structure at right angles to the first, which allowed two-dimensional viewing of a waveform. This two-dimensional display is fundamental to the oscilloscope.
Jonathan Adolf Wilhelm Zenneck
Zenneck in 1951
|Died||8 April 1959(aged 87)|
|Alma mater||University of Tübingen|
|Awards||IEEE Medal of Honor (1928)|
|Doctoral advisor||Theodor Eimer|
In 1885, Zenneck entered the Evangelical-Theological Seminary in Maulbronn. In 1887, in a Blaubeuren seminary, Zenneck learned Latin, Greek, French, and Hebrew. In 1889, Zenneck enrolled in the University of Tübingen. At the Tübingen Seminary, Zenneck studied mathematics and natural sciences. In 1894, Zenneck took the State examination in mathematics and natural sciences and the examination for his doctor's degree. His dissertation, supervised by Theodor Eimer, was on grass snake embryos.
In 1894, Zenneck conducted zoological research (Natural History Museum, London). Between 1894 and 1895, Zenneck served in the military.
In 1895, Zenneck left zoology and turned over to the new field of radio science, He became assistant to Ferdinand Braun and lecturer at "Physikalisches Institut" in Strasbourg, Alsace. Nikola Tesla's lectures introduced him to the wireless sciences. In 1899, Zenneck started propagation studies of wireless telegraphy, first over land, but then became more interested in the larger ranges that were reached over sea. In 1900 he started ship-to-coast experiments in the North Sea near Cuxhaven, Germany. in 1902 he conducted tests of directional antennas. In 1905, Zenneck left Strasbourg since he was appointed assistant-professor at the Danzig Technische Hochschule and in 1906, he became professor of experimental physics in the Braunschweig Technische Hochschule. Also in 1906, Zenneck wrote "Electromagnetic Oscillations and Wireless Telegraphy", the then standard textbook on the subject). In 1909, he joined Badische Anilin und Sodafabrik in Ludwigshafen to experiment with electrical discharges in air to produce bound nitrogen as fertilizer.
Zenneck analyzed solutions to Maxwell's equations that are localized around an interface between a conducting medium and a non-conducting medium. In these solutions, the electric field strength decays exponentially in each medium as distance from the interface increases. These waves are sometimes called Zenneck waves. Zenneck analyzed plane wave solutions having this property; he also analyzed solutions with cylindrical symmetry having this property.
Around World War I, Zenneck went to the front as a Captain in the Marines. However, in 1914, the German government sent him and Karl Ferdinand Braun to the United States as technical advisor in a patent case involving Telefunken. The US Marconi Company was sue Telefunken for patent infringement, a case spurred by the British government in an attempt to shut down transatlantic wireless telegraph between the US and Germany. The case stalled and then went moot when the United States entered the war, declaring Zenneck a Prisoner of War. He was dismissed only in 1920 when he could finally take over the professorship of experimental physics at the Technische Hochschule in Munich. In that time he resumed propagation studies, now with shortwaves and was first in Germany to study the Ionosphere with vertical sounding at his station at Kochel/Bavaria. From the 1930s, Zenneck directed the Deutsches Museum in Munich, and rebuilt it after World War II. Zenneck was awarded the 1928 IRE Medal of Honor for his achievements in basic research on radio technology and for fostering academic and technical offspring he received the Siemens-Ring in 1956.
- Jonathan Zenneck,”Über die Fortpflanzung ebener elektromag netischer Wellen längs einer ebenen Leiterfläche und ihre Beziehung zur drahtlose n Telegraphie” (“On the propagation of plane electromagnetic waves along a planar conductor surface and its relation to wireless telegraphy”), Ann. Physik  23, 846 (1907).
- Electromagnetic oscillations and wireless telegraphy (Gr., Elektromagnetische Schwingungen und drahtlose Telegraphie). F. Enke, 1905.
- Microwaves and electroacoustics (Gr., Hochfrequenztechnik und Elektroakustik). Volume 1. Academic publishing company Geest & Portig., 1908
- Wireless telegraphy. McGraw-Hill Book Company, inc., 1915.
- IEEE Global History Network (2011). "IEEE Medal of Honor". IEEE History Center. Retrieved 8 July 2011.
- Marton, L. (1980). "Ferdinand Braun: Forgotten Forefather". Advances in electronics and electron physics. 50. Academic Press. p. 252. ISBN 978-0-12-014650-5. Retrieved 2011-01-19.
- Reiss, David (1996). "Electromagnetic Surface Waves". The Net Advance of Physics: SPECIAL REPORTS, No. 1. MIT. Retrieved 2013-05-13.
- Barlow, H.; Brown, J. (1962). Radio Surface Waves. London: Oxford University Press. pp. v, vii.
- Carlson, W. Bernard. Tesla: Inventor of the Electrical Age, Princeton University Press - 2013, page 377
- General information
- Jonathan Zenneck (1871–1959)
- Physik Departments an der Technischen Universität München, "Booklet". Chapter 11. History (PDF)
- "Legacies: Jonathan A Zennick 1871 - 1959". IEEE History Center. Archived from the original on 2006-05-22.
- Zenneck, J. (1901). "Gravitation". Encyklopädie der mathematischen Wissenschaften mit Einschluss ihrer Anwendungen (in German). 5: 25–67.[permanent dead link]