"Rudolf Kompfner in 1942 —notably after his public announcement in 1946— when he was secretly working on microwave vacuum tubes for the British Admiral

"Rudolf Kompfner in 1942 —notably after his public announcement in 1946— when he was secretly working on microwave vacuum tubes for the British Admiralty at the University of Birmingham during World War II. But the history of this device is more complex because the traveling-wave tube was, consecutively, discovered thrice independently" https://hal.archives-ouvertes.fr/hal-01754885/document https://hal.archives-ouvertes.fr/hal-01754885/document