ABSTRACT
In-phase current is a current whose phase is close to constant or at least does not change sign along the antenna wire. The possibility of antenna operation in a wide frequency range is determined by the properties of the radiator, whose length is larger than the wavelength. Comparison of directional properties of radiators with different current distribution shows that the radiators with in-phase currents allow obtaining the higher level of directivity and this level is preserved in a wide range of frequencies. The radiators with in-phase currents allow to obtain a higher level of directivity, which is preserved in a wide range of frequencies. Equivalent replacement of a complex structure of high-frequency radiators by a structure with constant charges placed on conductors sharply simplifies the problem, reducing it to the electrostatic problem. The field amplitude and phase of each radiator depend on its structure and location in the antenna.
