Low profile satellite antenna

#1. Field of the Invention

#The invention relates to satellite antennas. More specifically, the invention relates to an inexpensive to manufacture, for example, Satellite Digital Audio Radio (SDAR) antenna having a low profile, for example, suitable for mounting on a motor vehicle.

#2. Description of Related Art

#FIG. 1a shows an exploded isometric view of a first embodiment of the invention.

#FIG. 1b shows a side view of antenna elements of a first embodiment of the invention.

#FIG. 1c shows a top view of antenna elements of a first embodiment of the invention.

#A first embodiment, shown in FIGS. 1a-1c, has a cover 10 that mates to a base plate 120. The base plate 120 may be metal or metal alloy, formed for example, by die-casting. The cover 10 may be formed, for example, by injection molding using a RF transmissive insulating material, such as polycarbonate, acrylic or other plastic material. The cover 10 may be shaped to create an environmental seal against the base plate 120, isolating the antenna elements and circuitry from water and other contaminant infiltration. Application of a sealing adhesive and/or a gasket (not shown) aids the environmental seal integrity.

#A printed circuit board (PCB) 80 which may contain electrical components 110 on its underside, e.g., at least one low noise amplifier and/or tuning/filter circuitry has a ground plane trace which mates with contact points of the base plate 120 creating a common ground plane for the antenna which extends through the base plate 120 to a vehicle body upon which the antenna may be mountable. Antenna leads 90, for example shielded co-axial cable, for SDAR-satellite and SDAR-terrestrial may be attached to dedicated low noise antenna amplifiers fed via 90 degree hybrid couplers 115 on the PCB 80. The leads 90 may be routed through a hole 130 in the base plate 120 for connection to a vehicle SDAR receiver antenna inputs wire harness via coaxial connectors 100.

#An insulator 40 may be located on a top side of the PCB 80. As shown in FIG. 1b, the insulator 40 may be formed from a dielectric substrate and has a thickness H2, of at least 3 millimeters, for example, 3.175 millimeters. Suitable materials for insulator 40 include, for example, polystyrene, polyphenolic oxide or other, for example, low cost materials with a suitable dielectric constant in the range of about 2-10. A, for example, circular shaped radiator element 60, having a diameter D2 (FIG. 1c) of, for example, 40 millimeters, attached to the insulator 40, receives SDAR-satellite signals. The radiator element 60 has two feeds 70 through the insulator 40 coupled to the PCB 80. The feeds 70 may be physically arranged at 90 degrees to each other with respect to a center of the radiator element 60.