The original inventor was not Japanese. During World War II, Professor Yagi of Tokyo Institute of Technology developed a radar, which was not taken seriously by the Japanese government. Even his application for a Japanese national patent was not approved. The United States invited him to give lectures in the United States, and the "Yagi antenna" technology he obtained was used in the Pacific battlefield. , making the radar of the US fleet superior to that of the Japanese fleet. In several key naval battles, the victory of the US military had a lot to do with this radar.