Coaxial collinear antennas with out-of-phase excitation of the elements

The paper deals with the capabilities of multielement antennas represented by rigid coaxials "embedded" in one another to form serial coaxial dividers of the antenna feed. Features of such antennas are analyzed by a well-known approximate method. According to this method, patterns are calculated using simplified current distributions represented by circular trigonometric functions. Subsequently, there are determined parameters of equivalent transmission lines with losses. Here, input impedances are estimated by applying a thorough analysis of both the excitation circuit and the radiating structure replaced by equivalent transmission lines. The present paper shows the practicability of such antennas that have out-of-phase excitation of the elements and provide quasioptimal patterns of cosecant shape having a radiation peak at the ground.