Beam adjusting device

The present invention relates to a device for adjusting the beam direction of an antenna. The device has a source connection terminal to be connected to a signal source and at least two feed connection terminals to be connected to antenna element feed points. A feed line structure is elongated in a main direction at a distance from and in parallel to a fixed ground plane on at least one side of said feed line structure, wherein a movable dielectric element is located between said feed line structure and said ground plane so as to change the signal phase of signal components being transferred between said source connection terminal and the respective feed connection terminals. The device includes means for allowing said ground plane to be positioned relatively close to said feed line structure without risking accidental contact between said feed line structure and said ground plane.