Émile Girardeau (12 October 1882 – 7 December 1970) was a French engineer, famous for being the first person to patent the original system of frequencies that is used and known today as radar.
In his early life he attended the École Polytechnique (Polytechnic School) (1902-1908) and became the Instructor at the École nationale des ponts et chaussées (National School of Bridges and Roads).
By 1910, Girardeau established the first radiotelegraphic radio connection in tropical countries with Joseph Béthenod.
In 1922, Girardeau set in motion the idea for the creation of a public utility of information and music.
In 1939, Girardeau built with Maurice Ponte radar installations for the defence of Paris against planes (which were destroyed in June 1940).