Abstract: A flat antenna for mounting on windowpanes of motor vehicles reduces the dimensions of the mass reference area of the mass plane, and the structural height without unfavorably influencing the functions and operating parameters of the antenna. The mass reference area has a trough-like shape, is centrally positioned under an aerial segment, and has conductive coating impermeable to the operating frequency of the antenna. The inside and outside conductors of the coaxial feed cable are connected to the aerial segment and mass reference area shifted to outside the aerial elements and thereby enables a significant reduction in overall dimensions.

Abstract: The flat-topped antenna apparatus includes a GPS antenna, a mobile radio antenna, a common housing for the antennas mounted over a ground plane and coaxial cables (12,13,13a) acting as electrical supply lines for the antennas. The mobile radio antenna includes a metal sheet (6,6',6a) plane parallel to the ground plane and spaced at a distance (A,A') of 0.04 of an average operating wavelength of a mobile radio frequency band from the ground plane. The metal sheet is electrically connected at an input terminal (11) with an inner conductor (10) of one coaxial cable (13,13a) and also with the ground plane via a short circuit element (7,7a). The GPS antenna is above and rests on the mobile radio antenna and includes a dielectric plate (1,1a) provided with a metal layer (3) connected at an input terminal (4) with an inner conductor (10) of another (12) of the coaxial cables.