Current distribution along loaded passive elements longer than half wave and its applications in antenna design

This paper presents some interesting features of current distribution along longer straight-loaded passive elements. As it has been shown, passive element current distribution may significantly differ from the sinusoidal-like distribution of fed element, even for thin elements if they are longer than halfwave. Based on such phenomenon simple Yagi-Uda antenna with straight longer dipoles tuned by means of lumped reactance is proposed. This antenna has the same gain as Landstorfer modification of Yagi-Uda antenna, while last one is ∼25% wider and its dipoles has complicated 2D shape.