Karl Ferdinand Braun (German: [ˈfɛʁdinant ˈbʁaʊ̯n] ; 6 June 1850 – 20 April 1918) was a German applied physicist who shared the 1909 Nobel Prize in Physics with Guglielmo Marconi for their contributions to the development of radio. With his two circuit system, long range radio transmissions and modern telecommunications were made possible. His invention of the phased array antenna in 1905 led to the development of radar, smart antennas, and MIMO. He built the first cathode-ray tube in 1897, which led to the development of television, and the first semiconductor diode in 1874, which co-started the development of electronics and electronic engineering.
Braun was a co-founder of Telefunken, one of the pioneering communications and television companies. He has been called the "father of television" (shared with inventors like Paul Nipkow), the "great-grandfather of every semiconductor ever manufactured", and a co-father of radiotelegraphy, together with Marconi, laying the foundation for all modern wireless systems.