Vehicle antenna glazing

Abstract

A vehicle antenna glazing comprising an antenna element that is a WIFI antenna working at 2.41-2.48 GHz frequencies and further comprises a planar radiating element 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 frequency, the antenna element comprising an array of two planar radiating elements connected to a co-axial connector, each of the planar radiating elements being made of a monopole, and the two planar radiating elements being parallel to each other, wherein each of the two planar radiating element is fed with a different signal phase.

2. The glazing according to claim 1, wherein the antenna element is a wide band or multi-band WIFI antenna element working at a 2.41-2.48 GHz frequency.

3. The antenna element according to claim 2, wherein the antenna element is a wide band or multi-band WIFI antenna element working at a 5.1-5.8 GHz frequency.

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

5. The glazing according to claim 1, wherein at least one of the planar radiating elements comprises a planar conducting material.

6. The glazing according to claim 5, wherein the planar conducting material is selected from the group consisting of a thin metal-based coating, a silver print, or a fine mesh of thin conducting wires.

7. The glazing according to claim 1, wherein at least one of the planar radiating elements comprises at least one slot etched in the planar conducting material.

8. The glazing according to claim 1, wherein at least one of the planar radiating elements is fed by electromagnetic coupling.

9. The glazing according claim 1, wherein the glazing comprises a laminated windshield having at least outer and inner panes of glass, the outer pane of glass having faces 1 and 2 and the inner pane of glass having faces 3 and 4, where face 2 is an inner face of the outer glass pane, face 3 is an inner face of the inner glass pane, and face 4 is an outer face of the inner glass pane of the windshield.

10. The glazing according to claim 9, wherein the antenna element is provided in face 2, face 3 or face 4.

11. The glazing according to claim 9, wherein the glazing is a heated, coated windshield.

12. The glazing according to claim 1, wherein at least one of the planar radiating elements comprises at least one parasitic element.

13. The glazing according to claim 12, wherein the at least one parasitic element is configured to shape a radiation pattern emitted by at least one of the planar radiating elements.

Description

(1) 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:

(2) FIG. 1 to FIG. 5 are an examples of implementing particular embodiments of the present invention.

(3) For avoidance of doubt, the terms external and internal refer to the orientation of the glazing during installation as glazing in a vehicle.

(4) Also for avoidance of doubt, the present invention is applicable for all means of transport such as automotive, train, plane . . . .

(5) 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.

(6) FIGS. 1a and 1b represent an embodiment of the present invention. The antenna element 1 is a single band, coplanar waveguide (CPW) fed 3, planar monopole. The radiating element 2 is made of for example a thin monopole (can be metal deposition or thin wire). The feeding structure 3 is the CPW structure.

(7) 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 and 1.6 mm thick for the internal glass sheet and joined by means of a thermoplastic sheet 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.

(8) A connector 9 for a coaxial cable is used to make the transition between a coaxial cable 10 and the feeding structure.

(9) 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).

(10) According to another embodiment of the present invention as shown in FIG. 2, a planar CPW-fed monopole 3 with parasitic element 4 may be used. At least one parasitic element 4 can be added close to the main radiating element 1, in order to shape the radiation pattern according to the application requirements. 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. It can be located in the same or in another layer of the glazing structure as the main element.

(11) According to another embodiment of the present invention as shown in FIG. 3, an array of two radiating elements 2 is used to enable the possibility to shape the radiation pattern, by feeding them with different signal phases, and playing with the distance between the array elements.

(12) For instance, an array, comprising two monopoles, similar to the one shown in FIG. 1, can be used. In this embodiment, the array elements can be fed through a microstrip transmission line, a CPW 3 or any planar transmission line or waveguide. One of the branches of the feeding structure can include a phase shifting branch 6 to tune the relative feeding phases between the elements. The feeding structure can also comprise impedance transformers to match the radiating elements' input impedance to the feeding line impedance 7 (e.g. quarter wave transformers).

(13) According to another embodiment of the present invention and as shown in FIG. 4, a slot antenna 5 may be used. In this example, the radiating element is made of conducting material 8 (either deposited on glass, or a thin wire dense mesh), in which slots are etched. The slots 5 can be used either as the main radiation source, or as impedance tuning elements. In the first case, the slots 5 can preferably be excited by electromagnetic coupling from a feeding structure located in another layer of the glazing structure. E.g. the slotted radiating element can be located in P2 or P3, while the feeding structure is located in P4, and connected to a connector making the transition from the feeding coaxial cable.

(14) According to another embodiment of the present invention as shown in FIG. 5, a PIFA (Planar Inverted F Antenna or a Yagi antenna may be used. The PIFA antenna 1 may be used and the radiating element may made of conducting material 8. The radiating element 2 is connected to a power system through a connector 9 and coaxial feed line 10.

(15) Thus antenna element 1 could be typically located in face 4 for a laminated glazing and excited by direct soldering of a connector. However, it could as well be integrated in face 2 or face 3 and be excited by electromagnetic coupling.

(16) 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.

(17) This embodiment relates to a windshield 1, ie a laminated glazing, however, it could be transposed to a glazing made in one pane of glass like sidelite, backlite . . . .

(18) The antenna element 2 according to the present invention is compatible with a heated glazing like a heated coated glazing or heated wired glazing. Both glazing are well-know and commonly used today, however, they may interfere with the efficiency of the antenna element.