Mitsubishi Electric CorporationKyoto University
No. 2931

MU Radar Developed by Mitsubishi Electric and Kyoto University
Receives IEEE Milestone
World’s first active phased array system for atmospheric radar has made important contributions
to atmospheric science and radar engineering
TOKYO, May 13, 2015 – Mitsubishi Electric Corporation (TOKYO: 6503) and Kyoto University announced
today that a middle and upper atmosphere radar (MU radar) that they jointly developed in 1984 has beenpresented with an IEEE Milestone by the Institute of Electrical and Electronic Engineers (IEEE), the world’s
largest academic society. The award recognizes the MU radar as the first large-scale mesosphere, stratosphere andtroposphere (MST) radar with a two-dimensional active phased array antenna system, and for its contributions toatmospheric science and radar engineering.
Kyoto University began design work on large atmospheric radars in the 1970s. Work focused initially on anincoherent scatter (IS) radar for observing the upper atmosphere for the first time in Asia. Studies then showedthat radars offering specific features are required to observe the middle atmosphere, which was referred to as “theunknown region” in those days. Research thereafter targeted designing a radar that could be used primarily toobserve the middle atmosphere and part of the upper atmosphere, which led to the development of the MU radar.
Kyoto University adopted the active phased array radar technique for high-resolution observation of important
wave motions in the atmosphere. Mitsubishi Electric started jointly developing the radar system, which waspartially completed in 1983. The design featured 57 antennas with an output power of 120 kW. An entire systemwith 475 antennas (103 m in diameter) and an output power of 1 MW was completed in 1984. Researchers andengineers from Mitsubishi Electric and Kyoto University have conducted technical meetings on a regular basis
since the beginning of the MU radar’s development. The radar system, which has been continually refined, hasproduced useful results for many scientific fields, including space and atmospheric physics, meteorology,
astronomy, electrical and electronic engineering, and astrophysics. The MU radar, now one of the world's best
atmospheric radars, has contributed much to science and engineering.
IEEE established the Milestones Program in 1983 to recognize achievements in the 20th century, or the “Centuryof Giants,” in which the professions and technologies represented by IEEE were developed. Each milestone
recognizes a significant technical achievement that occurred at least 25 years ago and had a regional impact. Todate, more than 100 Milestones have been dedicated around the world. Japanese entities have already received
Milestones for a directive short wave antenna, the Mount Fuji Radar System and the Tokaido Shinkansen (bullettrain).
The IEEE Milestone plaque has been installed at the Shigaraki MU Observatory at Kyoto University’s ResearchInstitute for Sustainable Humanosphere located in Koka, Shiga Prefecture.
About the Institute of Electrical and Electronic Engineers (IEEE)
IEEE was established in 1963 with the merger of the American Institute of Electrical Engineers (AIEE; founded in1884) and the Institute of Radio Engineers (IRE; founded in 1912). As the world’s biggest academic society, it
covers the fields of electricity, electronics, information and communications. It is based in the U.S.A. IEEE
membership exceeds 420,000 people from more than 190 countries (as of 2012), with more than half basedoutside the U.S.A. There are nine branches and 14,298 members in Japan (as of November 2014).

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MU Radar Specifications
ProductMU radar (Middle and Upper Atmosphere Radar)

Center Frequency

Sigaraki MU Observatory
Research Institute for Sustainable HumanosphereKyoto University
Kouyama, Sigaraki, Koka, Siga 529-1812, Japan
46.5MHz

Bandwidth

3.5MHzAntenna

475 sets of three sub-element crossed Yagi antennas

Structure

Circular antenna array measuring 103m in diameter

Function

Electronic beam steering

Beam width

3.6º (half-power full width)

Output power

1 MW (peak-envelope power)

URL

http://www.rish.kyoto-u.ac.jp/mu/en/

Location

Aerial view of MU radar

Antenna area of MU radar
IEEE MILESTONE IN ELECTRICAL ENGINEERINGAND COMPUTINGThe MU (Middle and Upper Atmosphere) Radar, 1984
In 1984, Kyoto University built the MU (Middle and Upperatmosphere) radar as the first large-scale MST (Mesosphere,Stratosphere, and Troposphere) radar with a two-dimensional active
phased array antenna system, with the collaboration of Mitsubishi
Electric Corporation. The MU radar enabled continuous and flexible
observation of the atmosphere, and has contributed to the progress ofatmospheric science and radar engineering.
May 2015

IEEE Milestone plaque (left) and text of the plaque citation (right)

Inquiries
Public Relations Division
Mitsubishi Electric Corporationprd.gnews@nk.Mitsubishi Electric.co.jp
www.MitsubishiElectric.com/news
Mamoru Yamamoto
Research Institute for Sustainable HumanosphereKyoto Universityyamamoto@rish.kyoto-u.ac.jp

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###About Mitsubishi Electric Corporation
With over 90 years of experience in providing reliable, high-quality products, Mitsubishi Electric Corporation(TOKYO: 6503) is a recognized world leader in the manufacture, marketing and sales of electrical and electronicequipment used in information processing and communications, space development and satellite communications,consumer electronics, industrial technology, energy, transportation and building equipment. Embracing the spiritof its corporate statement, Changes for the Better, and its environmental statement, Eco Changes, Mitsubishi
Electric endeavors to be a global, leading green company, enriching society with technology. The company
recorded consolidated group sales of 4,323.0 billion yen (US$ 36.0 billion*) in the fiscal year ended March 31,
2015. For more information visit: http://www.MitsubishiElectric.com*At an exchange rate of 120 yen to the US dollar, the rate given by the Tokyo Foreign Exchange Market on March31, 2015

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