It provides a significant gain over the 1/4-wave monopole. The best impedance match is provided when the radials are angled downward from the vertical at a 45-degree angle, causing a 1/2-wave dipole antenna effect. A ground plane antenna exhibits a circular coverage pattern, perpendicular to the vertical element. The antenna should be positioned so that the radials are closest to the nearest boundary such as a central location on the floor, wall or ceiling and functions best when inverted.