An Axisymmetric Secant-Square Beam Shaped Ceiling-Mounted Antenna

This paper proposes an axisymmetric secant-square beam-shaped ceiling-mounted antenna. Six folded Inverted-F Antennas (IFAs) are positioned on one side of a circular metal ground and are rotationally fed by a microstrip feeding network located on the opposite side of the ground. The vertical components of the folded IFAs primarily radiate the main energy, while the horizontal components radiate secondary energy, a phenomenon analyzable through the mirror principle. By adjusting the height of the folded IFAs, the radiation ratio between the horizontal and vertical components can be tailored, thereby shaping the beam. The Root Mean Square Error (RMSE) of the gain curves at 2.4 GHz is 1.66 dB, indicating a strong fit.