VEHICLE ANTENNA GLAZING

Abstract

A vehicle antenna glazing that includes an antenna element. The antenna element is a WIFI antenna working at a 2.41-2.48 GHz frequencies, and the antenna element includes a planar radiating element and a planar ground element, both connected to a co-axial connector.

Claims

1. A vehicle antenna glazing comprising an antenna element, wherein the antenna element is a WIFI antenna working at a 2.41-2.48 GHz frequencies, the antenna element comprising a planar radiating element, and a planar ground element, both connected to a co-axial connector.

2. A glazing according to claim 1, wherein the antenna element is a wide band or multi-band WIFI antenna element working at 2.41-2.48 GHz and 5.1-5.8 GHz frequencies.

3. A glazing according to claim 1, wherein the planar ground element is located between the radiating element and a closest glazing edge, and extends essentially parallel to the closest glazing edge.

4. A glazing according to claim 1, wherein the antenna element further comprises a planar feeding structure.

5. A glazing according to claim 1, wherein the planar radiating element and ground element are made of a planar conducting material such as a thin metal-based foil, a silver print, or a fine mesh of thin conducting wires.

6. A glazing according to claim 1, wherein the planar radiating element, the planar ground element and the planar feeding structure are adhered to the glazing by a thin adhesive layer.

7. A glazing according to claim 1, wherein the planar radiating element further comprises at least one parasitic element.

8. A glazing according to claim 5, wherein the planar radiating element, the ground plane element or extension thereof further comprises at least one slot that is etched in the conducting material.

9. A glazing according to claim 1, wherein the glazing is a laminated windshield.

10. A glazing according to claim 9, characterized in that wherein the antenna element is provided in face 4.

11. A glazing according to claim 1, wherein the glazing is a coated or heated coated windshield.

12. A glazing according to claim 11, wherein a grid pattern is decoated locally above the antenna element.

Description

[0030] Other advantages, as well as appropriate achievements and developments of the invention are developed in the claims and in the description of embodiments with reference to the figures which show:

[0031] FIG. 1 to FIG. 4 are examples of implementing particular embodiments of the present invention.

[0032] For avoidance of doubt, the terms “external” and “internal” refer to the orientation of the glazing during installation as glazing in a vehicle.

[0033] Also for avoidance of doubt, the present invention is applicable for all means of transport such as automotive, train, plane . . . .

[0034] For simplicity, the numbering of the glass sheets in the following description refers to the numbering nomenclature conventionally used for glazing. Thus, the face of the glazing in contact with the environment outside the vehicle is known as the side 1 and the surface in contact with the internal medium, that is to say the passenger compartment, is called face 2. For a laminated glazing, the glass sheet in contact with the outside environment the vehicle is known as the side 1 and the surface in contact with the internal part, namely the passenger compartment, is called face 4.

[0035] FIGS. 1a and 1b represent an embodiment of the present invention. The antenna element 1 is a single band, coplanar waveguide (CPW) fed 3, PIFA (Planar Inverted F Antenna) antenna. The radiating element 2 is made of, for example, a thin strip of conducting material (can be metal deposition or thin wire). The feeding structure 3 is the CPW structure, going through the ground element (11), the latter being essentially parallel to the closest glazing edge (19).

[0036] The antenna element 1 may be implemented in a laminated glazing, more particularly a windshield. The glazing may comprise two glass sheets for example 2.1 mm thick for the external glass sheet (15) and 1.6 mm thick for the internal glass sheet (13) and joined by means of a thermoplastic sheet (14) of 0.76 mm made of, for example, polyvinylbutyral. According the present invention, the antenna element 1 is provided out of the driver's vision and more particularly in a hidden zone. The conductive material (8) comprising the radiating element (2), ground element (11) and feeding structure (3) is sticked to the glazing thanks to an adhesive layer (16), and optionally covered by a protective layer (17) made, for instance, of some thin plastic sheet.

[0037] A connector 9 for a coaxial cable is used to make the transition between a coaxial cable 10 and the feeding structure (3). The connector (9) connects the inner conductor of the coaxial cable (10) to the feeding structure (3), and the outer conductor of the coaxial cable (10) to the ground element (11).

[0038] In this particular case, the antenna structure 1 should be preferably located in face 4, also called P4, as the connector 9 cannot be laminated because of its thickness (too thick). The connector 9 should then be hidden behind plastic covers inside the car (A-pillar or central bracket).

[0039] According to another embodiment of the present invention as shown in FIG. 2, a planar CPW-fed (3) antenna with a parasitic element 4 may be used. At least one parasitic element 4 can be added close to the main radiating element 2, in order to shape the radiation pattern according to the application requirements, or to create additional resonances, providing a multi band behavior. This at least one parasitic element 4 is electrically isolated from the main radiating element 2 (not connected to it). The at least one parasitic element 4 is made of conducting material, which can be the same or of another type than the main radiating element 2.

[0040] According to another embodiment of the present invention, illustrated in FIG. 3, representing a planar folded monopole antenna, the feeding structure 3 may be implemented as a gap (18) between the radiating element (2) and the ground element, or an extension (12) thereof.

[0041] According to another embodiment of the present invention and as shown in FIGS. 4a and 4b, slots (5) may be used. In these examples, slots are etched either in the radiating element (2) or the ground element (11) or an extension thereof (12), respectively. FIG. 4a describes a CPW-fed PIFA antenna, with slots (5) etched in the main radiating element (2), in order to tune the antenna impedance or create new resonances and open new frequency bands. In FIG. 4b, the slots (5) are etched in an extension (12) of the ground plane (11) and are used as the main radiation source.

[0042] According to an embodiment of the present invention, a black enamel, commonly used to mask all not aesthetics elements like connectics, sensors . . . may be provided on face 2. It is understood that the enamel or any masking band may be provided in face 2 and/or face 3 and/or face 4.

[0043] This embodiment relates to a windshield, ie a laminated glazing, however, it could be transposed to a glazing made in one pane of glass like sidelite, backlite . . . .

[0044] The antenna element (1) according to the present invention is compatible with coated glazing, such as infrared rejection glazing, or heated coated glazing and with heated wired glazing. Both glazing are well-know and commonly used today, however, they may interfere with the efficiency of the antenna element. Therefore, in a preferred embodiment, when applied on a glazing comprising a metallic coating, this coating may be partially removed in the glazing area located just above the antenna element. This local decoating enables to recover most of the antenna performance. In a more preferred embodiment, the decoated surface may take the form of a regular grid made of an array of intersecting thin decoated lines. The spacing between parallel lines of the grid should be smaller than the wavelength, preferably smaller the quarter of the wavelength.