Jonathan Adolf Wilhelm Zenneck (15 April 1871 – 8 April 1959) was a German

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and

electrical engineer Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

who contributed to researches in radio circuit

performance A performance is an act of staging or presenting a play, concert, or other form of entertainment. It is also defined as the action or process of carrying out or accomplishing an action, task, or function. Management science In the work place ...

and to the

scientific Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...

and educational contributions to the literature of the pioneer radio art. Zenneck improved the Braun

cathode ray tube A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms ( oscilloscope), ...

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 An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetiti ...

Early years

Zenneck was born in Ruppertshofen,

Württemberg Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart. Together with Baden and Hohenzollern, two other historical territories, Württ ...

. In 1885, Zenneck entered the Evangelical-Theological Seminary in

Maulbronn Maulbronn () is a city in the district of Enz in Baden-Württemberg in southern Germany. History Founded in 1838, it emerged from a settlement, built around a monastery, which belonged to the Neckar Community in the Kingdom of Württemberg. In ...

. In 1887, while in a Blaubeuren seminary, Zenneck learned

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

, and

Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...

. In 1889, Zenneck enrolled in the

University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-W� ...

. At the

Tübingen Seminary Tübingen (, , Swabian: ''Dibenga'') is a traditional university city in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, and developed on both sides of the Neckar and Ammer rivers. about one in t ...

, he studied

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

and

natural sciences Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeat ...

. 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 Gustav Heinrich Theodor Eimer (22 February 1843 – 29 May 1898) was a German zoologist. He was a popularizer of orthogenesis, a form of directed evolution through mutations that made use of Lamarckian principles. Life and work Eimer was born ...

, was on

grass snake The grass snake (''Natrix natrix''), sometimes called the ringed snake or water snake, is a Eurasian non-venomous colubrid snake. It is often found near water and feeds almost exclusively on amphibians. Subspecies Many subspecies are recognized ...

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s. In 1894, Zenneck conducted zoological research (Natural History Museum,

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

). Between 1894 and 1895, he served in the military.

Middle years

In 1895, Zenneck left zoology and turned over to the new field of radio science, He became assistant to

Ferdinand Braun Karl Ferdinand Braun (; 6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of radio and television technology: he shared the ...

and lecturer at "Physikalisches Institut" in

Strasbourg Strasbourg (, , ; german: Straßburg ; gsw, label= Bas Rhin Alsatian, Strossburi , gsw, label= Haut Rhin Alsatian, Strossburig ) is the prefecture and largest city of the Grand Est region of eastern France and the official seat of the ...

Alsace Alsace (, ; ; Low Alemannic German/ gsw-FR, Elsàss ; german: Elsass ; la, Alsatia) is a cultural region and a territorial collectivity in eastern France, on the west bank of the upper Rhine next to Germany and Switzerland. In 2020, it had ...

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''Random House Webster's Unabridged Dictionary''. ; 1856 – 7 January 1943 ...

's lectures introduced him to the wireless sciences. In 1899, Zenneck started propagation studies of

wireless telegraphy Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental technologies for ...

, 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 Cuxhaven (; ) is an independent town and seat of the Cuxhaven district, in Lower Saxony, Germany. The town includes the northernmost point of Lower Saxony. It is situated on the shore of the North Sea at the mouth of the Elbe River. Cuxhaven ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

. in 1902 he conducted tests of

directional antenna A directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions allowing increased performance and reduced interference from unwanted sources. Directional antennas provide increased performanc ...

s. In 1905, Zenneck left Strasbourg since he was appointed assistant-

professor Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professo ...

at the Danzig Technische Hochschule and in 1906, he became professor of experimental

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which ...

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 Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

. In 1913, he became director of the newly created Physics Institute of the Technische Hochschule München. Zenneck analyzed solutions to

Maxwell's equations Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits ...

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 wave The Zenneck wave, Zenneck surface wave or Sommerfeld-Zenneck surface wave is a longitudinal, inhomogeneous or non-uniform electromagnetic plane wave incident at the complex Brewster's angle onto a planar or spherical boundary interface between tw ...

s. Zenneck analyzed

plane wave In physics, a plane wave is a special case of wave or field: a physical quantity whose value, at any moment, is constant through any plane that is perpendicular to a fixed direction in space. For any position \vec x in space and any time t, ...

solutions having this property; he also analyzed solutions with cylindrical symmetry having this property.

Later years

Around

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

, Zenneck served on the front-lines as a

captain Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police department, election precinct, e ...

in the

Marines Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refl ...

. However, in 1914, the German government sent him and

Karl Ferdinand Braun Karl Ferdinand Braun (; 6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of radio and television technology: he shared the ...

to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

technical advisor In film production, a technical advisor is someone who advises the director on the convincing portrayal of a subject. The advisor's expertise adds realism both to the acting and to the setting of a movie. Nipo T. Strongheart was a noted technica ...

in a patent case involving

Telefunken Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company'). The name "Telefunken" ap ...

. The US

Marconi Company The Marconi Company was a British telecommunications and engineering company that did business under that name from 1963 to 1987. Its roots were in the Wireless Telegraph & Signal Company founded by Italian inventor Guglielmo Marconi in 189 ...

sued 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.Carlson, W. Bernard. Tesla: Inventor of the Electrical Age, Princeton University Press - 2013, page 377 The case stalled and event went moot when the United States entered the war, declaring Zenneck a

Prisoner of War A prisoner of war (POW) is a person who is held captive by a belligerent power during or immediately after an armed conflict. The earliest recorded usage of the phrase "prisoner of war" dates back to 1610. Belligerents hold prisoners of ...

. He was dismissed only in 1920 when he could finally take over the professorship of experimental physics at the Technische Hochschule München. In that time he resumed propagation studies, now with shortwaves and was first in Germany to study the

Ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...

with vertical sounding at his station at Kochel/

Bavaria Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total l ...

. From the 1930s, Zenneck directed the

Deutsches Museum The Deutsches Museum (''German Museum'', officially (English: ''German Museum of Masterpieces of Science and Technology'')) in Munich, Germany, is the world's largest museum of science and technology, with about 28,000 exhibited objects from ...

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and ...

, and rebuilt it after

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

. Zenneck was awarded the 1928

IRE Medal of Honor The IEEE Medal of Honor is the highest recognition of the Institute of Electrical and Electronics Engineers (IEEE). It has been awarded since 1917, when its first recipient was Major Edwin H. Armstrong. It is given for an exceptional contributio ...

for his achievements in basic research on radio technology and for fostering academic and technical offspring he received the

Siemens-Ring The Werner von Siemens Ring (in German orthography, Werner-von-Siemens-Ring) is one of the highest awards for technical sciences in Germany. It has been awarded from 1916 to 1941 and since 1952 about every three years by the foundation ''Stiftung ...

in 1956.

Patents

* *

Bibliography

Articles

*Jonathan Zenneck,”Über die Fortpflanzung ebener elektromagnetischer 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).

Books

* 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.

References

;Citations ;General information

(1871–1959) * Physik Departments an der Technischen Universität München, "
Booklet
'". Chapter 11. History (

PDF Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. ...

) * *

External links

* * {{DEFAULTSORT:Zenneck, Jonathan 1871 births 1959 deaths German electrical engineers Technical University of Munich faculty Presidents of the Technical University of Munich IEEE Medal of Honor recipients Werner von Siemens Ring laureates Commanders Crosses of the Order of Merit of the Federal Republic of Germany 19th-century German engineers 20th-century German engineers 20th-century German physicists Telecommunications engineers University of Tübingen alumni Engineers from Baden-Württemberg People from Ostalbkreis