Radio antennas

Hidetsugu Yagi: inventions and patents

Hidetsugu Yagi was a professor at Tohoku Imperial University in Sendai. An IEEE Milestone dedicated in 1995 records that from 1924 he and his assistant Shintaro Uda designed and built a directive short wave antenna in the university's laboratories. Uda first described the antenna in 1925 and Yagi published an English version in the IRE Proceedings in June 1928. Yagi's two US patents on the work were assigned to the Radio Corporation of America. The National Diet Library says he later became a professor at Osaka Imperial University in 1932 and received the Order of Culture in 1956. The National Diet Library and the International Union of Radio Science give his dates as 28 January 1886 to 19 January 1976.^1,2,3,4,5

Patents

Inventions

• Directive short wave antenna, 1924. A directional antenna for short waves developed at Tohoku Imperial University with Shintaro Uda.¹

Recognition

• 1995 IEEE Milestone, Directive Short Wave Antenna, 1924, dedicated 17 June 1995 at Tohoku University¹
• 1956 Order of Culture⁴

Sources

1. IEEE History Center, Engineering and Technology History Wiki, Milestones: Directive Short Wave Antenna, 1924 (accessed 2026-10-28)
2. Google Patents, US1745342A Directive-projecting system of electric waves (accessed 2026-10-28)
3. Google Patents, US1860123A Variable directional electric wave generating device (accessed 2026-10-28)
4. National Diet Library, Japan, YAGI Hidetsugu, Portraits of Modern Japanese Historical Figures (accessed 2026-10-28)
5. International Union of Radio Science, Hidetsugu Yagi 1886-1976, URSI Radio Science Bulletin no. 197 (1976) (accessed 2026-10-28)