EP1399986B1 - Antenna window with high frequency component - Google Patents

Abstract

The antenna disc (1) has an electrical high frequency component (HF) permanently mounted on one of its surfaces and electrically connected to a conductor structure (3) provided on the disc. The high frequency component has at least one flat coupling electrode (5) that is held at a defined distance from the flat conducting structure carrying the HF signal and separated by a dielectric intermediate layer (4).

Description

The invention relates to an antenna window with a high-frequency electrical component fixedly disposed on one of its surfaces and a conductor structure which is electrically connected to the component.

The DE-A1-198 23,202 discloses a vehicle antenna device, in which the foot connections of all the antennas arranged on a transparent glass pane (gathered together) at contact points of a contact field are surrounded by a plastic base disposed on the surface of the window, in which a high frequency component, for example an amplifier, is detachably fixed. For electrical connections between the high frequency component and the contact points, spring contacts are used here. These are simple to assemble and disassemble, but they are at the same time relatively sensitive to corrosion and mechanical vibrations that occur.

The DE-A1-198 56 663 discloses a device for contacting an antenna disposed on a window pane with an amplifier housing fixed to the window pane. The connection zone is surrounded by a layer of adhesive, while the electrical contacts are preferably made by brazing. The US Patent 6,087,996 shows a similar arrangement with spring contacts, wherein the amplifier housing is detachably attached to the glass surface with a Velcro fastener.

Over there DE-A1-197 35,395 , it is known to couple a conductive flat layer serving as an antenna on a glass (glass) capacitively transparent to a connecting conductor, with which the signal antenna is routed to the radio receiver. In this case, the capacitive coupling is performed in such a way that a strip-shaped electrode is printed on the face of a laminated pane facing the passenger compartment, while the conductive layer is disposed on a surface located internally in the composite. The length of the strip-shaped electrode must be more than 5 cm, and its width 5 to 10 mm.

The document DE-A1-198 58,299 shows an antenna system for a data communication device in a vehicle: on both sides of a dielectric mounting surface such as glazing, can be connected together by capacitive coupling of antenna system components arranged on flat coupling electrodes.

The documents US 4931805 and US 4931806 describe a telephone antenna placed on the window of a vehicle: an outer module carries the antenna while an inner module is connected to this antenna by capacitive signal transmission. The glazing is used as a dielectric. Both modules are attached to the glazing surfaces by double-sided tape.

The document DE 19627052 A1 describes a capacitive connection according to the prior art.

The document US 6,164,984 describes an electronic component with a galvanic connection using an adhesive glue.

The object of the invention is to provide, from a known window with a high-frequency component, another connection variant for contacting the high-frequency component disposed on the surface of the window.

According to the invention, this objective is achieved by using an antenna pane according to claim 1.

The features of the secondary claims indicate advantageous variants of this object.

A multitude of antenna signals can also be transmitted capacitively in a high frequency component, with negligible damping losses, even without clean contact points, by means of a flat electrode. For this purpose, it is first necessary to provide on the glass a flat conductor structure leading the antenna signals. This may be diversity antenna signals for radio and TV reception. It can also be more combined radio / TV and radiotelephone signals, GPS and the like. These signals can be filtered and exploited separately in the high-frequency component by means of suitable components, in particular amplified and restored later.

Naturally, the two coupling electrodes must completely overlap, because the capacitance is proportional to the surface of the electrodes. Incomplete overlap leads to a reduction in coupling capacity and thus to an increase in low frequency damping. It will be possible to ensure said covering as a rule in that the conductor structure used as a coupling point is extended on the surface of the pane in the form of a coupling electrode, respectively surface associated, of such so that small differences of position remain harmless.

A great advantage of this arrangement is that the high frequency component can be realized under the shape of a simple plate without galvanic contact towards the glass. As a general rule, the high frequency component will be glued to the surface of the glass. When it includes its own housing, only external electrical connections must still be made after bonding. When the high-frequency component does not have its own housing, it can - naturally after a thorough operation check - be overmolded durably with an appropriate mass. The ambient influences are thus substantially hermetically removed, although the high-frequency component must not itself have a clean sheath. This also contributes to the decrease of its projection above the surface of the window. Precisely in the case of application of the antenna window in a vehicle, reliable protection against moisture and water vapor is essential.

The width of the capacitive transmission zone is achieved by means of a double-sided adhesive tape of defined thickness, which on the one hand directly forms a dielectric intermediate layer between the conductor structure on the side of the glass and the electrode coupling of the high frequency component. On the other hand, the fixing of the high frequency component is in this way very greatly simplified. The material of the adhesive tape provides long-lasting compliance with the desired width, respectively the distance of the electrodes from the capacitive transmission area.

Another advantage of this arrangement is the short path of the signal from the antenna to the high frequency component, especially when it includes an amplifier. Because both losses and disruptive influences remain very weak in this way. The high frequency component may also include, for example, one or more tuners and the like in addition to one or more amplifiers.

Similarly, the replacement of a possibly defective component is not particularly complicated. The overmolding mass can be removed, possibly together with the component that has become unusable, and the bonded assembly can be removed, with no particular operation necessary to detach the contacts, just as with spring contacts.

It goes without saying that the arrangement described here of a high-frequency component on an antenna window can be used both on glass panes and on plastic panes, naturally also both on monolithic panes and on glass panes. laminated windows.

The connection between the conductor structure and the antenna elements as well as the manufacture and nature of the latter will not be discussed further here, because many embodiments and combinations have been previously described in the state of the art.

However, it must be noted that the transmission of the signals from the conductor structure to the coupling electrode under the high-frequency component is not limited to a single zone or transmission capacity. On the contrary, it is also possible to divide the conductor structure (printed or glued) into several electrically separated parts, each of which is connected to an antenna field or the like. In other words, several coupling points can thus be locally close on a glass surface. The signals carried by them are coupled in parallel in the high frequency component covering this plurality of transmission capacities by means of a corresponding number of coupling electrodes individually associated spatially and functionally.

It is thus possible to gather locally, for example at a point on a surface of the window, signals of antenna structures, which are distributed over several panes (for example side windows and rear windows), as can be expected especially in diversity antenna systems. It should be noted, however, that in such multiple solutions, too small contact distances (conductor portion portions relative to one another) can lead to signal crosstalk. To reduce or avoid this effect, the distance between two contact faces should be greater than the lengths of the contacts edges distant from this distance.

Other details and advantages of the subject of the invention will appear by the drawing of an exemplary embodiment and by its detailed description which follows.

The single figure shows, in a simplified representation (without a particular scale), a section through the edge region of an antenna window, on which a high frequency component is durably fixed by means of an adhesive tape. double sided.

A transparent monolithic glass pane 1 carries, near the edge of one of its surfaces, both an opaque coating 2 and a conductor structure electrically conductive 3 disposed on the latter. The opaque coating and the conductor structure are preferably made in known manner by screen printing with corresponding pastes, which can then be fired (on a glass pane). Opaque coating 2 must not be electrically conductive. On the other hand, the conductor structure 3 is preferably made in a known manner with a screen paste of high silver content, as is known by current collector strips for printed and baked heating conductors or also for heating layers. on car windows. Ideally, the conductor structure 3 can also, in the present case of application, have another function of being a collector array of this type. In a known manner, antenna structures can also be used as heating elements, when they are supplied with a supply voltage from the on-board network.

On the conductor structure 3 is again fixed, by means of a thin double-sided adhesive tape 4, a high-frequency component HF, to which we will return even further.

Between the conductor structure 3 and the adhesive strip could be, according to the end customer's request, another visually opaque masking layer, which is not electrically conductive.

In the mounted state of the antenna pane 1 in a vehicle body (not shown), this device is generally located on a surface facing the interior of the vehicle, and is masked inwards by a coating inside. The opaque coating 2 hides the conductor structure 3 and the RF high frequency component visually outwardly.

A thin flat electrode 5 made of a good conducting metal, for example copper, is assembled directly with the adhesive strip 4.

The adhesive strip 4 forms a dielectric separation layer of defined thickness between the conductor structure 3 and the flat electrode 5. Its thickness determines the distance of the two electrodes, which should not exceed about 0.5 mm, and thus takes a decisive part in the capacitive transmission behavior of the device.

No galvanic contact is required between the conductor structure 3 and the high frequency component HF. On the contrary, the conductor structure 3 serves as the first electrode of a capacitive coupling of signals in the high-frequency component HF by the flat electrode 5. The thickness of the electrode can range from 10 to 100 μm and the surface area is about 900 mm ² . In the case of the example, the latter has a length of about 100 mm, a width of 10 mm and a thickness of 35 microns. The conductor structure at this point has a width of more than 10 mm and a thickness of 4 - 15 μm with a silver content of> 70% and a specific resistance of 2.85 - 5.45 * 10 ^-6 [Ω * cm]. Thus, satisfactory transmission behavior has been achieved in the frequency range above 40 MHz, so signals for VHF, FM, UHF, etc., are transmitted safely and in good quality. The attenuation remains low, thus a loss of 0.69 dB was measured only between 76 MHz and 860 MHz (respectively frequencies for the FM and UHF signals).

The geometric dimensions of the hardware components can be kept constant in narrow tolerances. It is important that the layer adhesive does not allow penetration of moisture. An acrylate glue in the form of a film or foam, the permittivity of which is between 2 and 4, is preferably used.

Thus, a total capacitance suitable for the transmission of high frequency signals from the conductor structure 3 to the flat electrode 5 in subsequent components of the high frequency component HF is formed.

The flat electrode 5 is on the other side connected to a relatively thick elastic layer 6, preferably glued again, which can and must compensate for slight curvatures of the surface of the glass 1. The flat electrode 5 itself is thin enough to follow any significant curvature of the surface in practice. These bends therefore have only a negligible influence on the width of the slot respectively on the thickness of the adhesive strip 4. Next is a carrier plate 7, which forms the mechanical rear armature of the high frequency component HF. Depending on the mounting environment, this carrier plate may be rigid or flexible. On it is fixed a carrier plate 8 with electronic equipment that there is no need to further clarify. It may also, like the carrier plate, be rigid or flexible depending on the requirements imposed, if the mounting environment requires (eg very small radii of curvature of the glass surface at the mounting location) or if the high frequency component has relatively large surface dimensions.

Finally, a signaling cable 9 is electrically connected to the carrier plate, respectively to conductive tracks formed thereon. Signals are transmitted by this signal cable 9 (shielded) more than 5μm thick to downstream devices not shown here (radio or TV receivers, telephones, etc.); in addition, it serves to supply the RF high frequency component with electrical current and possibly to connect it to the ground.

All this device is coated with an overmolding mass 10, which firmly adheres to the surface of the antenna pane 1, respectively to the opaque coating 2 and hermetically protects the high-frequency component HF against moisture and fouling.

Claims (7)

1. Antenna window (1) comprising:

   - a high-frequency electronic component (HF) placed fixedly on one of its surfaces, the component (HF) comprising high-frequency electronic equipment and a mounting plate (8) for the high-frequency electronic equipment; and

   - a conductor structure (3) electrically connected to the component (HF) and conducting high-frequency antenna signals, the component (HF) and the conductor structure (3) being on the same side of the window, the component (HF) being above the conductor structure (3),

   characterized in that said electrical connection is formed by capacitive coupling and without any galvanic contact, the flat conductor structure (3), forming a first electrode for said coupling, is kept at a defined distance from a second flat electrode (5) for said coupling by means of an intermediate dielectric layer (4) formed by a double-sided adhesive tape of defined thickness, the second coupling electrode (5) being thin enough to follow a curvature of the surface of the window, and in that the component (HF) includes a support plate (7) bearing on one of its faces the second coupling electrode (5), the mounting plate (8) being fixed to the other face of the support plate (7).
2. Antenna window according to the preceding claim,
   characterized in that the component (HF) fastened to the window (1) is overmoulded, so as to be hermetically sealed against air and water vapour, by means of a cured compound (10) bonding to the surface of the window.
3. Antenna window according to any one of the preceding claims, characterized in that the flat conductor structure (3) consists of an electrically conducting paste to be baked, which is printed and baked on one surface of the window (1).
4. Antenna window according to any one of the preceding claims, characterized in that it comprises antenna elements consisting of an electrically conducting paste to be baked, which is printed and baked.
5. Antenna window according to any one of the preceding claims, characterized in that the flat conductor structure is connected, in an electrical or capacitive manner, to antenna elements that are placed on another surface of the window, in particular inside a laminated window.
6. Antenna window according to any one of the preceding claims, characterized in that the flat conductor structure is divided into several parts conducting signals, which parts are distant and electrically separated from each other, with which a corresponding number of coupling electrodes for coupling the component (HF) are associated, thus forming a plurality of coupling points.
7. Antenna window according to any one of the preceding claims, characterized in that the conductor structure on the surface of the window (3), which is used as a coupling point, is produced with a larger surface area than the surface area of the second flat coupling electrode associated with the component (HF).

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