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Hidetsugu Yagi

Hidetsugu Yagi
Born (1886-01-28)January 28, 1886
Died January 19, 1976(1976-01-19) (aged 89)
Nationality Japanese
Fields Physics
Notable awards Blue Ribbon Award (1951), the Order of Cultural Merit (1956) and the Large Asahi Award of the First Class (1976)

Hidetsugu Yagi (八木 秀次 Yagi Hidetsugu, January 28, 1886 - January 19, 1976) was a Japanese electrical engineer from Osaka. When working at Tohoku University, he wrote several articles that introduced a new antenna design by his colleague Shintaro Uda to the English-speaking world.

The Yagi antenna, patented in 1926, allows directional communication using electromagnetic waves, and is now installed on millions of houses throughout the world for radio and television reception. He also tried, unsuccessfully, to introduce a wireless power transmission system. He participated in establishing the Chiba Institute of Technology.[1]

He was the fourth president of Osaka University from February 1946 to December 1946.[2]

In 1942, he became Director of the Industrial Sciences Faculty of the Tokyo University, in year 1944 he became General Director of the Technology Institute, and in year 1946 also General Director of the Osaka Imperial University. He was decorated with the Medal of Honor with Blue Ribbon Award in 1951, with the Order of Culture in 1956, and posthumously with the Grand Cordon of the Order of the Rising Sun in 1976.


  • Biography 1
  • Wireless communication 2
  • References 3
  • External links 4


Hidetsugu Yagi was born on January 28, 1886 in Osaka Prefecture. After he graduated from the Department of Electronic Engineering of the Tokyo Imperial University, Faculty of Sciences, in 1909, he studied from 1913 in England, America, and Germany, and in Germany he continued research of generation of electric waves used for wireless communication. He returned to Japan in 1930.

Wireless communication

A three-element Yagi-Uda antenna used for amateur radio. The longer reflector element (left), the driven element (center), and the shorter director (right) each have a so-called trap (parallel LC circuit) inserted along their conductors on each side, allowing the antenna to be used at two different frequency bands.
Six rooftop Yagi-Uda television antennas in Israel. The Yagi-Uda design is widely used at VHF and UHF frequencies, since at these wavelengths, the lengths of the elements are conveniently small.

The topic of wireless communication, which he pursued during his studies abroad, would become a research theme to which he would dedicate his entire life. In 1919, he became a professor at the Faculty of Engineering Sciences of the Tohoku Imperial University which was then established and during the same year he also attained the title of doctor of engineering sciences. He was able to foresee that short waves or ultra short waves would become the main element for communication using radio waves and he aimed his research in this direction. This resulted in the publication of his papers called "Generation of Short Wavelength Waves", "Measuring Specific Wavelengths with Short Wavelengths", and other papers. The so-called Yagi antenna is based on these published articles. He invented it as an antenna using his "method for directional electric waves". He obtained the patent rights to his invention (patent number 69115, issued in 1926).

Because this invention uses a very simple construction, it enabled directional communication with electric waves. This construction is still used basically in any type of antenna which is used today for ultra short or extremely short waves.

On April 18, 1985, the Japan Patent Office selected him as one of Ten Japanese Great Inventors.[3]


  1. ^ Chiba Institute of Technology history
  2. ^ Osaka University history
  3. ^ "Ten Japanese Great Inventors". Japan Patent Office. 

External links

  • Yagi page on the Japan Patent Office site
  • Historical page about Yagi at Georgia Institute of Technology
  • on a motor trader's websiteGreat Japanese Inventors of History
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