Patent ID: 7030827

Claim:
An antenna system, comprising: a cylindrical waveguide tube having a bottom plate and a tube portion; a planar antenna adapted for exciting a TE 01 -mode and arranged in the cylindrical waveguide-tube, wherein the planar antenna includes: a substrate of dielectric material having a first surface intended to face towards a filling good surface and a second surface facing in an opposite direction, wherein the second surface of the planar antenna is arranged parallel to and at a distance to the bottom plate such that a spacing is provided; a first group of a plurality of dipole arms arranged on the first surface or the second surface on a perimeter of a circle with a predetermined radius, wherein the dipole arms of the first group extend in a first direction; a second group of a plurality of dipole arms arranged on the first surface or the second surface on the perimeter of the circle with the predetermined radius, wherein the dipole arms of the second group extend in a direction opposite the first direction.