EP1920495B1 - Multiband antenna system - Google Patents

Abstract

The invention relates to a multiband antenna system for a vehicle window comprising an antenna feed structure (7) in lateral recesses (5) of the heat conductor field (1, 2). The antenna feed structure (7) is connected to the heat conductor field (1, 2) at high-frequency with a low-impedance, but is not galvanically connected thereto. The inventive system allows defrosting of the vehicle window in the entire wiper area without impairment by the antenna feed structure (7).

Description

State of the art

The invention relates to an antenna arrangement, in particular for a vehicle window pane with a heating conductor field, in particular on or in a vehicle window pane, and an antenna conductor structure which is coupled in a high frequency manner to the heating conductor field.

Such an antenna arrangement is known from DE 39 10 031 A1 known. A similar antenna arrangement shows the WO 02/056412 A2 , There two antenna elements are provided for diversity evaluations.

The WO 99/66587 shows an antenna arrangement for diversity operation. The Heizleiterfeld a motor vehicle window pane is used in conjunction with additional galvanic not connected to the Heizleiterfeld and located between Heizleiterfeld and the upper edge of the vehicle window line structures as an antenna for the reception of LMK, FM and optional TV signals.

Antenna arrangements are also known which form antennas for LMK and FM reception from the galvanically contacted heating conductor field. Here are Bordnetzentkoppelnde filter elements for FM / TV and LMK reception due to the galvanic connections between antenna connection point and heating conductor necessary ( EP 0269723 B1 ). The heating conductors are substantially horizontal and substantially parallel to the metallic boundaries of the disc. The on-board network interference transmitted by the heating current to the heating conductors serving as antenna must be are known to be suppressed by modules with high-frequency high-impedance behavior when the antenna connection point is galvanically connected to the Heizleiterfeld. For FM / TV reception, these are, for example, rod core chokes, which are integrated into the heating current-supplying line parts and are usually located near the heating current connections of the heating conductor field.

For the LMK reception, this is a current-compensated toroidal core choke (AM blocking circuit), which is likewise arranged in the heating current supply. This AM blocking circuit is a very cost-intensive module whose own weight (about 200 g) leads to high mechanical loads on both the printed circuit board and the screwing points and is thus to be evaluated as extremely critical in the context of quality assurance. The vibrations occurring under normal driving conditions cause solder joints to be heavily stressed. In compact vehicles, this AM-blocking circuit is often mounted in the rear tailgate, so that when slamming the flap accelerations of about 50 g can occur and the entire component tears off the screwing points.

Also known are antenna arrangements in laminated glass panes, such as front windows of cars. Here are the antenna wires in the space between the two glass panes, whereby an increased effort in contacting arises. The contacting is often realized with so-called flat cables, which are introduced during the production process in the laminated safety glass. After mounting the disc in the vehicle, this flat cable is then connected to an electronic module.

The document EP 0 559 196 A1 relates to a generic multigrade antenna assembly comprising, inter alia, a glass pane antenna, wherein in the disc, a heating element is introduced. The likewise arranged in the disc antenna also has in the heating field on lateral recesses, wherein an antenna conductor structure outside of the heating field, that is arranged substantially in the lateral recesses of the heating field.

The document US 2004/0056810 A1 discloses a glass antenna having a first and a second antenna element, each capacitively coupled to a heater. The heating element serves to receive signals in two reception areas.

Finally, also reveals the US 5,877,727A a glass antenna for motor vehicles with a heating field.

Advantages of the invention

With the measures of claim 1, ie a Heizleiterfeld, in particular on or in a vehicle window with lateral recesses, an antenna conductor structure for at least two receiving areas outside the Heizleiterfeldes, which is arranged substantially in the lateral recesses of the Heizleiterfeldes, a high-frequency low-resistance but not galvanic coupling the antenna conductor structure with the Heizleiterfeld, which is effective for one of the at least two receiving areas, the reception of LMK and diversified VHF / TV signals in a single window pane is realized, the area to be heated is as large as possible. The uniform condensation of the disc is over the Conductor width of the sub-heating conductor, so on the resulting ohmic resistance of the heating conductors ensured.

In particular, the area which is swept by the windshield wiper in the case of the rear window of a compact vehicle can be completely heated without being affected by the antenna conductor structure, since this is arranged substantially in a lateral area outside the Heizleiterfeldes, which is not swept by the windscreen wiper ,

Thus, the arrangement according to the invention overcomes a significant disadvantage of the aforementioned antenna arrangements, namely the need for a surface, e.g. in the upper part of the window, which can not be heated due to the lack of heat conductors and therefore can not be defrosted. Especially in cars with small windows of the resulting heatable area is impermissibly small.

The multigrade antenna structure according to the invention has the particular advantage that the area which is swept over by a rear window wiper is heated completely or at least substantially. At the same time a separate antenna conductor is available, which can be designed without mutual influence to the heating field in terms of optimal reception behavior. For this purpose, the structure of the heating element is designed in particular in the middle region of the pane.

By dispensing with a galvanic contacting of the Heizleiterfeldes - the coupling is high frequency low impedance, for example, capacitive - electrical system interference that are transmitted via the heating current, the antenna function less affect and filter measures are much easier and cheaper to implement or may possibly completely omitted.

In the dependent claims advantageous embodiments of the antenna arrangement according to the invention are shown.

The invention relates to an antenna arrangement, which is characterized, inter alia, in that a first segment is provided, which fills the vehicle window in its full width and a second segment is provided in only a portion of the width of the vehicle window, which is swept by the free wiper end.

Furthermore, the invention particularly relates to an antenna arrangement, which is characterized in that the antenna conductor structure is provided for the at least two receiving areas substantially in that lateral portion / recess of the width of the vehicle window, which is not filled by the second segment.

drawings

• Figur 1 eine erfindungsgemäße Mehrbereichs-Antennenanordnung,
• Figur 2 die Heizleiterstruktur für eine gleichmäßige Beheizung,
• Figur 3 eine Mehrbereichs-Antennenanordnung mit zwei Antennenanschlusspunkten,
• Figur 4 eine Mehrbereichs-Antennenanordnung mit zwei Antennenleiterstrukturen, die galvanisch voneinander getrennt sind,
• Figur 5 eine Mehrbereichs-Antennenanordnung, deren zweite Antennenleiterstruktur im wesentlichen aus dem Heizleiterfeld gebildet ist,
• Figur 6 eine Mehrbereichs-Antennenanordnung mit FM-Diversity.

With reference to the drawings, embodiments of the invention will be explained. Show it

• FIG. 1 a multigrade antenna arrangement according to the invention,
• FIG. 2 the heat conductor structure for uniform heating,
• FIG. 3 a multigrade antenna arrangement with two antenna connection points,
• FIG. 4 a multigrade antenna arrangement with two antenna conductor structures which are galvanically separated from each other,
• FIG. 5 a multigrade antenna arrangement whose second antenna conductor structure is essentially formed by the heating conductor field,
• FIG. 6 a multi-range antenna arrangement with FM diversity.

Description of exemplary embodiments

FIG. 1 shows a vehicle-glass antenna for multi-range reception, in particular for LMK and FM reception with the concomitant use of Heizleiterfeldes. The heating conductors 3 are arranged parallel to one another. They open in a first segment 1, which fills the vehicle window in its full width, respectively at their left and right ends in a busbar 4. In the upper area, the Heizleiterfeld on a second segment 2, which is not over the full width of the vehicle window extends, but only over that area, which is swept by the free wiper end. The swept by the windshield wiper area 6 is shown as a dashed semicircle. The width of the second segment 2, which also has two busbars 4 and is connected in parallel at the outermost heating conductor of the first segment 1 in the upper region, is adapted to the sweeping region of the windshield wiper such that the entire wiper region can be defrosted. The lateral recesses 5 of the vehicle window, which arise because the second segment 2 is provided in only a portion of the width of the vehicle window are used by Antennenleiterstrukturen 7 without affecting the Scheiben Abtauung. In the FIG. 1 shown antenna conductor structure 7 consists of three parallel conductors in both the left and in the right recess 5. The antenna conductor 8 at the top connects the Antennenleiterstrukturen in the left and right recess. The parallel-guided individual conductors of the antenna conductor structure 7 are combined in the region of the right-hand recess at one point to form an antenna connection point 9. The associated mass point 10 is advantageously located in the immediate vicinity of the metallic body surrounding the vehicle window. An antenna signal amplifier 11 separately for AM (LMK range) and FM is in close proximity. About the subsequent RF cable 12, the antenna signals are routed to the radio 13. The supply voltage U _b to the amplifier 11 can be transmitted via the RF cable. The antenna connection point 9 is galvanically connected only to the antenna conductor structure 7, but not to the heating conductor field 1. The heating circuit consists of the heating conductors of the Heizleiterfeldes 1, the busbars 4, the FM chokes 14 and the heating current supply source 15th

The antenna conductor structure in FIG. 1 is especially designed so that resonant behavior occurs in the VHF range. At the same time, it is as long as possible to ensure sufficient reception performance for the LMK (AM) range and optimum mass reception capacity. In this embodiment, by the proximity of at least one antenna conductor of the antenna conductor structure to the heating field 1 in addition a high-frequency low-impedance, in particular capacitive, coupling, so that for FM frequencies practically the entire Heizleiterfeld is available as an effective antenna surface. By this high-frequency technology low-impedance coupling to Heizleiterfeld turn on board filter elements are necessary in this case. It is also possible to insert conductor parts into the pane, which are placed essentially not for reception but mainly for optical reasons in order to generate a uniform visual appearance.

The heating conductor structure of the pane is preferably formed so that the wiper area can be heated completely or at least substantially. The uniform heating of the upper section (segment 2) can according to FIG. 2 be realized as follows. The heating conductors are characterized by their resistance characterized. In this case, has a horizontal heating conductor of length L1 over the entire disc area an ohmic resistance R1. Starting from an approximately one-third of the heating field through the vertical conductors (L2 = L3 = 1/3 * L1), the parallel defrosting of the disk requires the parallel connection of the three horizontal heating conductors of length L2 shown in the middle section in conjunction with the series connection of the two resistors R3 are again ensured an ohmic resistance according to R1. The conductor width of conductor L1 is assumed to be a standard value of 0.5 mm. In addition, it is required that the conductor width of the conductors L2 and L3 (R2 = R3) is the same. In this case, the equivalent resistance of the top heating connection is given by: $$\mathrm{RGES}\mathrm{=}\mathrm{R}\mathrm{3}\mathrm{+}\mathrm{1}\mathrm{/}\mathrm{3}\mathrm{*}\mathrm{R}\mathrm{2}\mathrm{+}\mathrm{R}\mathrm{3}\mathrm{So\; RGES}\mathrm{=}\mathrm{R}\mathrm{3}\mathrm{+}\mathrm{1}\mathrm{/}\mathrm{3}\mathrm{*}\mathrm{R}\mathrm{3}\mathrm{+}\mathrm{R}\mathrm{3}\mathrm{=}\mathrm{7}\mathrm{/}\mathrm{3}\mathrm{*}\mathrm{R}\mathrm{3}$$

This equivalent resistance must match R1 resistor: $$\mathrm{R}\mathrm{1}\mathrm{=}\mathrm{7}\mathrm{/}\mathrm{3}\mathrm{*}\mathrm{R}\mathrm{Third}$$

Thus, the conductor width of the conductors L2 and L3 by a factor of 7/3 must be less than that of the conductor L1, so in this example about 0, 2mm.

The vertical conductor sections have a greater width in order to ensure the current distribution on the conductors L2. The heat conductor structure is usually applied by screen printing on the disc with the above-mentioned nominal width of 0.5 mm, so that also with regard to manufacturing tolerances of the screen, a continuous pressure of the conductors L2 and L3 (then with the width of 0.2 mm) is guaranteed.

The dimensioning of the strip width is of course only listed here by way of example. The exact dimensioning must be determined in conjunction with the size of the wheel, the wiper range and the manufacturing tolerances of the screen printing process.

The line structure is applied by conventional methods on a window pane, wherein it is irrelevant in the context of the invention, whether it is a window safety glass or laminated safety glass. Said window pane is surrounded by a metallic frame and usually designed as a rear window of a motor vehicle.

FIG. 3 shows a further embodiment in which a second antenna structure 71 is formed with a plurality of antenna conductors on the opposite left side with an antenna connection point 18 and a closely adjacent ground terminal 16. Optionally, TV reception is implemented by the connected electronic module 17. This is then a two-antenna system is formed to ensure diversified broadcasting and TV reception. The second antenna structure 71 is also capacitively coupled, in particular for VHF and / or TV reception, to the heating conductor field 1.

FIG. 4 shows a third embodiment in which the second VHF antenna is formed of a conductor pattern 71 which is not electrically connected to the conductor pattern 7 of the first antenna. Another advantage of the invention becomes clear at this point: When LMK reception is very crucial to the capacity of the antenna conductor relative to the vehicle mass. In the prior art system, in the two-antenna system, by connecting a second electronic subassembly having a certain input capacitance, the overall capacitance of the device relative to the antenna terminal 9 is increased. In other words, a part of the received LMK signal is grounded via the second module and thus degrades the overall reception. This circumstance is in an antenna arrangement according to the invention with separate antenna structures according to FIG. 4 avoided.

FIG. 5 shows an embodiment in which the second VHF antenna structure by galvanic contacting 19 of the Heizleiterfeldes 1 and a closely adjacent ground terminal 16 emerges. The second antenna structure is thus formed in this case essentially by the Heizleiterfeld. Other antennas may also be formed in the same way from the heating conductor field at a different location, eg two additional ones in order to generate a four-antenna system, in particular for diversity reception. The conductors 72 are provided either for design reasons only - symmetrical appearance - or are capacitively coupled to the conductors 7 to improve the resonance behavior and / or increase the antenna gain.

In FIG. 6 a second FM amplifier is inserted in the same mechanical component 11. The second FM antenna is formed by galvanic contacting 20 of the heating field 1, while the first FM antenna to the component 11 consists of the conductor structure 7 with the contact 9. The two outputs of the component 11 can either directly to the radio 13 with FM diversity supplied or alternatively, the supply to a separate Diversitybox is provided. Of course, the diversity logic can also be integrated in the component 11.

Claims (9)

1. Multiband antenna system, in particular for a vehicle windshield, having the following features:

   - a heating conductor field (1, 2) having lateral recesses (5), in particular on or in a vehicle windshield,

   - an antenna conductor structure (7) which is outside the heating conductor field (1, 2) and is arranged substantially in the lateral recesses (5) in the heating conductor field (1, 2),

   - the heating conductor field (1, 2) consisting of at least two contiguous segments (1, 2) which are arranged such that the heating conductor field (1, 2) substantially covers the entire wiper region of a vehicle windshield, and

   - the first segment (1) fills the entire width of the vehicle windshield and the second segment (2) extends in only a partial region of the width of the vehicle windshield, which partial region is swept over by the free wiper end,

   characterised by the following further features:

   - the antenna conductor structure (7) is adapted for at least two reception ranges,

   - a low-resistance but non-electric coupling, for high frequency, of the antenna conductor structure (7) to the heating conductor field (1, 2) is effective for one of the at least two reception ranges, and

   - the conductor line width of the heating conductors of a second segment (2) of the at least two contiguous segments (1, 2) is less than the conductor line width of the heating conductors of a first segment (1) of the at least two contiguous segments (1, 2) by such an amount that substantially uniform defrosting of the vehicle windshield is ensured.
2. Antenna system according to claim 1, characterised in that the antenna conductor structure (7) for the at least two reception ranges is arranged substantially in the lateral partial region/recess (5) of the width of the vehicle windshield which is not filled by the second segment (2).
3. Antenna system according to either claim 1 or claim 2, characterised in that the antenna conductor structure (7) is configured in such a way that it has a resonant response in the UHF reception range.
4. Antenna system according to any one of claims 1 to 3, characterised in that the antenna conductor structure (7) is selected in terms of its effective conductor length such that a sufficient reception performance in the AM range is provided.
5. Antenna system according to any one of claims 1 to 4, characterised in that the antenna conductor structure (7) consists of individual conductors which are guided in parallel and are combined at least at one point to form an antenna connection point (9), one of these individual conductors being capacitively coupled to at least one heating conductor of the heating conductor field (1, 2) such that the entire heating conductor field is available as an effective antenna surface for one reception range, preferably the UHF range.
6. Antenna system according to any one of claims 1 to 5, characterised in that at least one further antenna conductor structure (71) is provided for a further reception range and/or the diversity operation for one reception range.
7. Antenna system according to claim 6, characterised in that the further antenna conductor structure (71) is arranged opposite the antenna conductor structure (7) and is isolated by the second segment (2).
8. Antenna system according to either claim 6 or claim 7, characterised in that the further antenna conductor structure (71) is connected to the antenna conductor structure (7) via at least one conductor (8) which in particular extends over the free end of the second segment (2).
9. Antenna system according to either claim 6 or claim 7, characterised in that the further antenna structure (71) is electrically decoupled from the antenna structure (7).

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