Ladder antennas for dual circular polarization

A novel radiator, a ladder antenna, is proposed for a dual circularly polarized (CP) antenna. The ladder is formed by microstrip lines printed on a grounded dielectric substrate. The antenna is excited at the ladder-side ends: F_R and F_L. By changing the excitation points of FR and we can select the rotational sense of the CP radiation. In this paper, three types of ladder antennas are numerically analyzed: they are ladders along the y-axis, along the x-axis and a ladder array. The y-axis ladder is a prototype. After investigating the x-axis ladder, we realize the ladder array.