EP0897198A2 - Vehicle body of synthetic material with antennae - Google Patents

Abstract

The motor vehicle body includes rod shaped plastic elements which are provided with paths and areas with differently thick and preferably electrically well conducting metal layer. The metal layer are constructed so that a number of antennas are provided for the same and for different frequencies and that a ground reference and areas with shielding effects are provided. Emitter with different function principals are provided dependent on the operation frequency and on the required radiation pattern. Areas which act as radiator for one frequency are on ground potential for other frequencies. The antenna, ground reference areas and areas with shielding effect are preferably distributed over the entire area of the plastic elements. The plastic elements are metallised in two serial areas with a distance necessary for each operation frequency for specific antenna principals.

Description

The invention relates to motor vehicles in which the body at least in parts no longer in the conventional way from sheet metal or is produced as a self-supporting sheet metal body. It is becoming apparent that in the future parts or areas will increase the body and even complete plastic bodies be made or that you can frame structures with a Planking made of plastic understands. Plastics are also, with appropriate finishing, surface treatment and coating, find use as material for motor vehicle window panes.

Depending on the degree of substitution of the usual materials can create completely new terms and conditions for the Selection and execution of antennas for reception and / or Transmission mode and for their assignment to the vehicle. In addition comes that the number of antennas for different tasks, that need to be installed on the vehicle is increasing. So are in the Ultimately, quite a few new antennas with different ones Frequency ranges and radiation characteristics in addition to systems known today to integrate into the modern vehicle.

The new premises for the antenna configuration result above all from a changed influence on the electromagnetic field within which the vehicle is located or moves. So far, the vehicle body has presented itself as a kind of cuboid made of sheet metal. Part of the roof surface is usually based on rod-like elements, the spars, between which there are large, essentially rectangular openings - windows - which are sealed with dielectric material - glass panes. This structure is located just above the great mass of the earth's surface and is surrounded by an electromagnetic field that comes from a variety of sources, including the transmitters whose signals are to be received. The vehicle can also carry self-emitting emitters.
The metal parts of the body and the dielectric of the windows lead to a characteristic deformation of the surrounding field and to different field concentrations around the vehicle and in the area of the window openings. Signals from this field are primarily coupled out today with rod antennas and with radiator structures in the window panes. On the one hand, the metallic body supports, in certain areas, the function of the antennas as wave type converters and coupling elements, and on the other hand, the metal surfaces provide the necessary ground potential for the antennas.

If now some or all of the sheet metal surfaces of the vehicle are replaced by those made of plastic, then the field formation and field concentration around the vehicle is changed, and the mass potential, as the vehicle can be viewed, is missing or changes significantly.
The result is that the conditions for the selection and arrangement of the antennas change or that certain configurations can no longer be used or can only be used to a limited extent.

Also the introduction of plastic window panes and out Plastic / glass combinations result in changes. Let it be not in the same way with the new pane construction in the case of conventional glass panes, metal-ceramic conductor tracks apply in high temperature processes, and a use of such Conductor tracks and, for example, of inserted thin wires for heating purposes is questionable because of the temperatures required for heating.

There is a solution for the window heating: The plastic window is provided with a flat, electrically conductive metal coating that is connected to the DC electrical system. With a suitable arrangement of the heating current connections, uniform heating of the pane surface with surface temperatures which are not too high is then obtained.
However, a window pane with an - essentially - closed metal coating of good electrical conductivity is hardly suitable for the arrangement of wire and conductor track structures in the previous manner and for their use as antenna radiators.

The problem of assigning antennas to plastic body parts was, in a preliminary stage of the current development, in the German patent application No. 195 35 250 treated. A research, that was created in connection with the registration has one Series of property rights that provide a good overview of the present attempts and possibilities in this area. In the proposed solutions listed there is consistently of a conventional structure of the body and the execution in steel sheet, which is basically retained. Only individual parts of the bodies are made of non-metallic Materials. Antennas are attached to these parts. The antennas are e.g. in and under plastic roof shells, in the folding roof or the hardtop of a convertible, in the trunk or Bonnets and bumpers.

However, on the one hand, these solutions continue to build on the Presence of the sheet metal body of the body on - if only the resulting mass potential and the influence of the surrounding field is used; on the other hand, these have an effect Factors for certain possible antennas and frequency ranges also annoying.

Blechquader" als einzige Metallteile das Antriebsaggregat und Teile des Fahrwerks übrig bleiben, umgeben von Bauelementen aus dielektrischem Material mit evtl. unterschiedlichstem ε_r, und daß vielleicht ausgerechnet die Fensterscheiben - die bisher bevorzugt als Träger integrierter Antennen dienten - durch eine elektrisch gut leitende Metallbeschichtung für diese Aufgabe nicht mehr oder nur noch eingeschränkt geeignet sind. Man kann sagen, daß die durch ein derart beschaffenes Gebilde bedingte Felddeformation heute weder experimentell abzusehen noch mit vertretbarem Aufwand rechnerisch nachzubilden ist.
Es ist zu erwarten, daß sich hier die gebräuchlichen und bewährten Methoden der Antennenkonfiguration nicht anwenden lassen.The invention, on the other hand, is based on a condition which, in extreme cases, is that of the above

Blechquader "as the only metal parts the drive unit and parts of the undercarriage are left, surrounded by components made of dielectric material with possibly different ε _r , and that perhaps it was just the window panes - which previously served as carriers for integrated antennas - that have an electrically conductive metal coating for This task is no longer suitable or only suitable to a limited extent. It can be said that the field deformation caused by such a structure is neither experimentally foreseeable nor can it be simulated with reasonable effort.
It is to be expected that the usual and proven methods of antenna configuration cannot be used here.

The invention has for its object a basic solution and to find a way to motor vehicles whose body under partial to extensive use of flat parts Plastic is made to equip with antennas, as well as around the function of such antennas experimentally and arithmetically optimize. The antennas are preferably below that Select point of view that it integrated into the vehicle body can be and do not interfere with the shape flow of the body.

This task is performed with the in the generic terms of the main and the Features specified specified solved. The subclaims contain preferred versions and details.

The invention is not succinct in that the old State is restored under new signs, i.e. that e.g. with a continuous metal coating on the plastic parts or the coating of a complete plastic panel quasi-sheet metal car is manufactured. On the contrary, the invention uses the changed initial situation to the configuration of antennas to open completely new paths on the vehicle body and the thought the antenna integration into the vehicle body for the first time to be implemented in all consequences.

The entire vehicle becomes a complex antenna carrier, and the various radiators are arranged on and in it, where and how, according to their operating principle, they ensure the highest or optimal effect and can be implemented inexpensively. Compared to the known prior art, this means: gain in degrees of freedom for antenna design. All types of flat antennas which can be integrated into surfaces and which are known to the person skilled in the art are largely applicable, from conductor track structures, similar to the window pane antenna, and stripline antennas (patch antennas) via slot antennas to surface emitters and monopoles simulated on surfaces and dipoles. Metallized surfaces, which - whatever their function - lie behind the radiator structures, can be arranged at different distances from the radiators in front of them, due to the usual double-shell structure of most body elements today.
In addition to the functions as radiators and as ground reference surfaces (grounding surfaces), the metallization zones can be used for shielding purposes by arranging and designing them according to such functional requirements.

At the same time, in the form of the simulation model, a possibility was created to test all of these configurations and to measure and optimize them under largely realistic conditions and, due to the schematic structure of the model, to present them in a comparable manner in the computer simulation.
The simulation model enables the antenna developer to select and pre-configure an antenna type regardless of the availability of the vehicle to be equipped and the degree of replacement of metallic parts by plastic ones.
In this way, the problem is addressed that the antenna is often still regarded by the car manufacturers as an accessory and the antenna developer is given little time and hardly any intervention options to get one antenna- and reception-friendly environment "within the vehicle construction or to test innovations.
The model according to the invention not only permits broad testing and application of the different antenna principles known to the person skilled in the art in the novel vehicle constructions from which the invention is based; in the same way it enables the reproduction of conventional bodies for basic work as well as for the optimization of antenna systems.

The structuring of metallized surfaces according to the invention the bodywork, which defined by means of the simulation model can be on the plastic parts of a vehicle in the Final state no longer recognizable. They disappear under the paint insofar as they have been applied to the outer surfaces, or are - function-related - in areas not visible to the eye arranged.

Figur 1.

Groundplanes mit Dachkapazität
a) Zwei Strahler über einem großflächigen Massepotential
b) Zwei Strahler über Radials

Figur 2.

Schlitzantennen in einer Fensterscheibe mit einer Metallbeschichtung mit guter elektrischer Leitfähigkeit

Figur 3.

Antennen an Teilen der Karosserie-Beplankung
a) Zwei Kotflügel und eine Tür
a) Zwei Kotflügel und eine Tür
b) Tür
c) geschlossenes Dach

Figur 4.

Simulationsmodell mit verschiedenartigen Dachausbildungen
a) Grundkörper
b) unterschiedliche Dachteile

The invention is explained in more detail below on the basis of exemplary embodiments. In the accompanying drawing show a schematic representation

Figure 1

Ground planes with roof capacity
a) Two emitters over a large ground potential
b) Two radiators over radials

Figure 2.

Slot antennas in a window pane with a metal coating with good electrical conductivity

Figure 3.

Antennas on parts of the body panels
a) Two fenders and a door
a) Two fenders and a door
b) door
c) closed roof

Figure 4.

Simulation model with different roof designs
a) Basic body
b) different roof parts

In the example according to FIG. 1a, two vertical bars 17 are also included Roof capacity 17.1 on the side of a vehicle floor plate 1 arranged (groundplanes). The vertical bars can be used as Metallization of the B-spar 3 (continuous middle spar between the doors) and the roof capacity can be obtained by Metallization of the side roof spars. The base plate existed from sheet metal or from a continuously metallized material. The two radiators could act as antennas for radio reception in the FM range (as λ / 4 emitters) and in the AM range.

Figure 1b shows two rod radiators 18 with roof capacity 18.1, which were obtained by metallizing the A-pillars and sectionally metallizing the roof pillars above the windshield 12. The radials 19 are required as a ground potential if the body paneling around the base of the antennas is not metallized. These antennas would be suitable for radio reception in a convertible.
It is also conceivable that a rod-like or stripline-like metallization is led down to the base plate as a vertical rod.

In Figure 2 antennas are shown, which are suitable for discs 12, 13 made of plastic with a highly conductive metal coating 15. A flat, highly conductive metal coating may be necessary if, for example, you want to heat a motor vehicle rear window 13, which is made of plastic or plastic with a thin glass coating. The previously usual conductor structures cannot be applied to this pane material because the sintering processes require temperatures that are not conducive to the novel pane structure.
The metal coating 15 for the window heating must be transparent, but it must be so dense and well conductive that it heats up sufficiently and evenly when connected to a heating power source.

The lack of the usual conductor structures in the panes is also noticeable in the configuration of antennas - a metal coating with good electrical conductivity makes the window antennas common up to now largely ineffective.
In order to nevertheless arrange antennas in the window area, a window is assumed which is provided with a metal coating 15 only in the visible area and which is surrounded by a metal frame or metal-coated frame 16. Between the metallized area 15 and the frame 16 there is a narrow free strip 20 all around. This strip is used according to the invention for the formation of slot antennas 23 for different frequencies.
For this purpose, the slot length is defined by switching on RF-blocking means, for example short-circuit connections 21 and series resonant circuits 22. In the examples, the respective geometrical slot length is identified by the dimension arrows.
As the variants according to FIGS. 2a to c show, slot antennas of different lengths can be realized, which are placed next to one another - ie in a row along the strip 20 - and overlapping ". Overlapping arrangement means that, starting from a common connection point 21, 22, different lengths to two other connection points 21.1, 22.1 are realized. The connection point 21.1, 22.1, which is closest to the starting point, is dimensioned electrically so that it is blocking for the higher of the two frequencies and permeable for the lower. For the lower frequency, the connection point with the greater distance has a blocking effect.
An interesting application of this principle is that a slit can consist of a horizontal branch and a branch parallel to the side rail. In this way, fields with horizontal and vertical polarization components can be received cheaply.

In Figure 3 are antenna designs using other areas the body shown. The two slots 23 according to Figure 3a in Fenders 5 and in door 9 can be fed asymmetrically, to place the input impedance in low-resistance areas.

Due to the arrangement at right angles to one another, the reception of signal components of different polarization or, if connected in phase, the reception of circular polarization is possible. The slots are realized by continuously metallizing the surfaces surrounding them, or they are formed as skeletonized slots from strip conductors.
In the rear fender 6 in the example, a so-called thick half-wave dipole 24 is additionally provided for linear polarization. The folded slot radiator 25 in the door according to FIG. 3b also offers itself because of the relatively low input impedance which is characteristic of this slot design.
FIG. 3c shows a strip line array antenna (patch array) 26 in the roof 11 of a car. It is suitable for satellite reception in the GHz range. The required ground potential can be provided with the necessary distance in the direction of radiation in the form of a metallization of the roof lining.

• auf im wesentlichen waagerechten Bezirken der Karosserie vor allem Antennen mit Rundumstrahlung (für terrestrischen Betrieb) und solche mit nach oben gerichteter Keule, z.B. für Satellitenempfang, anzuordnen sind, und
• an im wesentlichen senkrechten Bezirken der Karosserie überwiegend Antennen mit Querstrahlung vorzusehen sind, wobei hier bei Erfordernis quasi-Rundumstrahlung erzielt wird, indem mehrere gleiche Antennen für einen Frequenzbereich allseitig am Fahrzeug angeordnet werden und die Signale summiert oder zu einer Mehrantennen-Anordnung mit Raum-Diversity kombiniert werden.

From the exemplary representation of different radiator principles suitable for the invention, it can be deduced that

• on essentially horizontal areas of the body, antennas with omnidirectional radiation (for terrestrial operation) and those with the beam pointing upwards, eg for satellite reception, must be arranged, and
• Antennas with transverse radiation are to be provided on essentially vertical areas of the body, whereby quasi-omnidirectional radiation is achieved if required by arranging several identical antennas for a frequency range on all sides of the vehicle and summing the signals or in a multi-antenna arrangement with spatial diversity be combined.

FIG. 4 shows the simulation model of a car according to the invention. It preferably consists of a rod structure which is planked as desired.
Depending on the requirements, the planking is partially or completely metallized and / or provided with metal surfaces structured according to the invention.
The model is preferably divided into a base body and add-on elements that can be added variably.
In a preferred embodiment, the base body consists of the base plate 1 and the framework up to the height of the belt line, plus the A-spar with the roof-side border of the windscreen area. The doors, bonnet and trunk lid are hinged.
The parts for the roof 11 and the B and C spars 3, 4 are added modularly as add-on parts and are interchangeable.
You can choose between a convertible and saloons with notchback and hatchback and a caravan-like training. Since only the roof 11 varies in its dimensions in the model itself, changes and additions can be made with little effort.
The framework principle also offers favorable conditions for the realization of double-skin cladding parts. So the actual conditions on the vehicle are easily simulated; At the same time, the formation of metallization areas with different tasks and with different distances to each other is supported.
The planking parts are made from different suitable plastics in order to largely realistically reproduce the conditions in practice, for example with regard to different relative dielectric constants.

In order to treat HF interference caused by the Vehicle electronics, etc. are generated, comparable conditions for the simulation model and for a vehicle with partial to to achieve extensive use of plastic elements assumed that at least the engine compartment of the vehicle against the other areas of the vehicle are shielded, e.g. largely is encapsulated.

Reference numerals

1

Base plate

2nd

A-spar

3rd

B-spar

4th

C-spar

5

Front fender

6

Rear fender

7

Engine Hood

8th

trunk lid

9

Front doors

10th

Rear doors

11

top, roof

12th

Windscreen

13

rear window

14

fixed side window

15

Metal coating

16

Pane border

17th

Vertical rod

17.1

Roof capacity

18th

Rod heater

18.1

Roof capacity

19th

Radials

20th

metal-free disc strips

21

Short circuit

21.1

Short circuit

22

Series resonant circuit

22.1

Series resonant circuit

23

Slot antenna

24th

Half wave dipole

25th

folded slot heater

26

Stripline group antenna

Claims (12)

Motor vehicle body, which consists at least in part of flat and rod-shaped plastic elements, the plastic elements being connected to antennas for reception and transmission on different frequencies, characterized by the following features: At least some of the plastic elements are provided with surfaces and tracks of a different thickness, preferably an electrically highly conductive metal coating, the metal coating is structured in such a way that on the one hand there are a number of antennas for the same and for different frequencies and on the other hand ground reference areas and areas with a shielding effect, which, depending on the operating frequency and the required radiation diagram, result in radiators with different functional principles, and surfaces which act as radiators for one frequency, belong to the ground potential for other frequencies, the antennas and ground reference areas generated by the structuring and areas with a shielding effect are preferably distributed over the entire area of the plastic elements, For certain antenna principles, the plastic elements are metallized in two levels one behind the other, with a functional distance that is essential for the respective operating frequency. Motor vehicle body made of plastic with antennas, according to Claim 1, characterized in that the separation of the well conductive areas due to non-conductive and only weak conductive, preferably strip-like areas, wherein especially the respective width of these areas is dimensioned for certain higher frequencies act separating and for comparatively lower frequencies are not recognizable, Motor vehicle body made of plastic with antennas, according to Claim 1, characterized in that rod antennas (17, 18) into rod-like elements of the body, such as A-spar (2) and B-spar (3), integrated and provided with roof capacities (17.1, 18.1) are. Motor vehicle body made of plastic with antennas, according to Claim 1, characterized in that several antennas (23, 24, 25) with directional characteristics all around preferably vertical surfaces (5, 6, 9, 10) of the body are and an all-round characteristic through in-phase Interconnection of the signals, in the manner of a sum diagram, arises. Motor vehicle body made of plastic with antennas, according to Claim 1, characterized in that several antennas (23, 24, 25) with directional characteristics all around preferably vertical surfaces (5, 6, 9, 10) of the body are and a multi-antenna arrangement for antenna diversity form. Motor vehicle body made of plastic with antennas, according to Claim 1, characterized by the use of Window panes (12) made of plastic and plastic / glass combinations each with an electrically good conductor Metallization (15), but which is optically transparent, wherein the metallization with a non-conductive border (20) is surrounded by such a width that the metallization acts as a separate surface for certain frequencies, which acts as Antenna is usable. Motor vehicle body made of plastic with antennas, according to Claims 1 and 5, characterized by the use of window panes (12) made of plastic and plastic / glass combinations each with a well conductive metallization, (15) which is however optically transparent, the Metallization preferably all around from a non-conductive Border (20) is surrounded in the slot antennas (23) are trained. Motor vehicle body made of plastic with antennas, according to Claim 1, characterized in that the body at least partially, preferably predominantly from frame parts consists, which preferably completely with a planking Plastic are provided and that in the plastic sheeting Antennas are integrated. Motor vehicle body made of plastic with antennas, according to Claims 1 and 7, characterized in that the frame parts are made of metal. Motor vehicle body parts made of plastic with antennas, according to claim 1 and 7, characterized in that the Frame parts are made of dielectric material. Device for experimental selection, positioning and dimensioning of antennas on plastic elements of a motor vehicle body, according to claims 1 to 9, characterized by the following features: the device consists of dielectric material and reproduces the shape and dimensions of a motor vehicle, preferably a passenger car, the device consists of a base plate (1) on which an at least partially variable frame is arranged, with which a limousine can be reproduced in different variants, whereby the flat parts are divided into sections which are to be attached to the elements of the framework according to the type of vehicle to be reproduced, the flat parts are preferably flat, the antenna structures and ground surfaces are formed on the parts of the framework and on the flat elements by means of foils and metallic layers of paint. Device according to claim 11, characterized by a Basic body that includes the vehicle up to the belt line A-spar (2) with border of a front screen (12) simulates, as well as various roof elements for the simulation different vehicle types.

Images