Yagi antenna - technical definition

Also known as Yagi-Uda antenna.A VHF or UHF vertical antenna array comprising a basic radiator (dipole) antenna supplemented by a slightly longer reflector element mounted directly behind the dipole and a slightly shorter director element mounted directly in front of the dipole. A Yagi antenna is used to improve the directional gain of a television antenna when reception is otherwise weak. Ham radio enthusiasts commonly use homemade Yagi-Uda antennas.The Yagi-Uda antenna was invented at Tohuku University in 1926 by Hidetsugu Yagi (1886