Patent Application
20090262024
The invention relates to a multilayer antenna having a planar design as claimed in the pre-characterizing clause of claim 1.
A generic multilayer antenna has become known from DE 10 2006 027 694 83.
The multilayer antenna having a planar design comprises in this case an electrically conductive earth surface, a conductive radiation surface (which is arranged with parallel spacing from the earth surface) and also a dielectric carrier which is sandwiched between the earth surface and the radiation surface. A support means, on which an electrically conductive patch element is positioned, is arranged above the radiation surface. The support means for the patch element has a thickness or height which is less than the thickness or height of the patch element.
The patch element itself can be configured as a volume body, i.e. as solid material. It is also possible for the patch element to consist of a metal plate or a metal sheet which is provided, for example by cutting or punching, with peripheral webs, edges or the like extending away from the dielectric carrier.
An antenna of this type is particularly suitable as a motor vehicle antenna, including for example for SDARS services. For this purpose, a patch antenna of this type can be provided in addition to further antenna radiators for other services on a common base assembly on antenna structures which are separate from the base assembly and generally protrude vertically upward.
An overall antenna assembly of this type is then located below a hood, such as is known for example from EP 1 616 367 B1.
In antenna assemblies of this type, for example using a patch antenna known from DE 10 2006 027 694 B3, which was mentioned at the outset, care must be taken to ensure that certain tolerances are adhered to. This certainly requires the availability of an additional small dimension of from 1-2 mm as tolerance compensation to avoid insufficient internal space within a hood. However, in hood-shaped covers, overall this certainly leads to a perceptible increase in the size of the hood as a whole, as even a small increase in the minimum height leads overall, owing to a specific curved configuration of the hood, to an undesirable widening and lengthening of the hood housing.
The object of the present invention is therefore to develop a further improved multilayer antenna having a planar design that allows a reduction in the tolerances to be adhered to even in the case of optimum antenna reception.
According to the invention, the object is achieved in accordance with the features disclosed in claim 1. Advantageous embodiments of the invention are disclosed in the sub-claims.
The multilayer antenna having a planar design corresponds basically to the construction known from DE 10 2006 027 694 B3. In this respect, reference is made to the disclosure of the above-mentioned prior publication and to the content of the present application.
The improvement may now be achieved as a result of the fact that the parasitic patch, which is provided on the planar patch antenna above the support means 19, is now divided at least into two and comprises a first patch element and also a patch additional element. In order to vary the overall height of the two patch elements, the elements can be collapsed telescopically to differing degrees; preferably, one patch element can dip into the other to differing degrees. One patch element may in this case preferably be configured in a box-shaped or box-like manner, preferably with a peripheral and upwardly open edge. The second patch element, which will be referred to hereinafter in some cases also as the patch additional element, may consist of or comprise a volume body or, for example, a likewise box-shaped radiation element, thus allowing both patch elements to be moved toward one another in a differing position in which one patch element, as it were, “dips” in the other by a certain height. In other words, preferably at least one of the two patch elements should therefore have a length and/or a width which is preferably at least slightly less than the internal dimension of the second patch element which is provided with a peripheral or generally peripherally closed edge [and can] if required dip therein to a certain degree. In this case, the further patch additional element pertaining to the parasitic radiator arrangement can, as mentioned, be provided as a volume body or else as a box-shaped element which is preferably downwardly open. However, in this case, the lower patch element can in particular also be equipped as a volume body or as a box-shaped patch element which is, for example, even downwardly open and can dip into the upper patch additional element, especially if it is configured to be slightly smaller (i.e. in the longitudinal and transverse directions) than the upper patch additional element.
This patch additional means is now fastened to the inside of the hood, which overlaps the entire antenna assembly, and/or is held thereby, in such a way that this patch additional means rests directly above the patch assembly which is located on the support means. Viewed from the side, there should in this case preferably be no interval between the edges or webs of the patch assembly, which is located on the support means, and the patch additional means located thereabove. However, in the event of differences in tolerance, it is then quite possible for the upper patch additional means to dip to differing degrees into the box-shaped patch element located on the carrier means, or else a gap is formed between the two.
In principle, the assembly can also be inverted in such a way that, for example, the patch element which is Fastened to the hood is made larger and provided with the aforementioned generally closed peripheral edge or web and in this case, if required, overlaps to differing degrees as required the patch element which is located therebelow and held by way of the actual patch antenna.
Overall, this assembly according to the invention allows the height of the hood to be reduced, as no additional (albeit only slight) height dimension must be provided for differences in tolerance. If there are differences in tolerance, this merely means that the patch element, which is held on the inside of the hood, can reach to differing degrees into the box-shaped patch assembly which is located therebelow and rests on the support means.
However, from the point of view of electrics, this split patch functions like the one-piece patch element described in the generic prior art according to DE 10 2006 027 694 B3.
Further advantages, details and features of the invention will emerge from the following discussion of the invention. In the individual drawings:
Reference will now firstly be made to the exemplary embodiment according to
The schematic cross section according to
The dielectric carrier 5 comprising an upper side 5a and a lower side 5b has a sufficient height or thickness which generally corresponds to a multiple of the thickness of the earth surface 3, i.e. in contrast to the earth surface 3, which roughly consists merely of a two-dimensional surface, the dielectric carrier 5 is configured as a three-dimensional body having sufficient height and thickness.
As an alternative to the dielectric body 5, a different type of dielectric or a different type of dielectric construction can also be provided, for example using air or with a layer of air next to a further dielectric body. If air is used as the dielectric, then obviously a corresponding carrier means, comprising for example stilts, bolts, columns, etc., must then obviously be provided to carry and to hold the further parts of the patch antenna which are located thereabove and will be described hereinafter.
An electrically conductive radiation surface 7, which can likewise again roughly be conceived of as a two-dimensional surface, is configured on the upper side 5a opposing the underside 5b (which comes to lie adjacent to the earth surface 3). This radiation surface 7 is electrically powered and excited via a feed line 9 which extends preferably in the transverse direction, in particular perpendicularly to the radiation surface 7 from below through the dielectric carrier 5 in a corresponding hole or a corresponding channel 5c.
From a connection point 11 which is generally located at the bottom and to which a coaxial cable (not shown in greater detail) can be connected, the inner conductor of the coaxial cable (not shown) is then electrically connected to the feed line 9 and thus to the radiation surface 7. The outer conductor of the coaxial cable (not shown) is then electrically connected to the earth surface 3 which is located at the bottom.
The exemplary embodiment according to
The radiation surface 7 resting on the dielectric 5 can have the same contour or outline 7′ as the dielectric 5 located therebelow. In the exemplary embodiment shown, the basic shape is likewise formed so as to be square, in adaptation to the outline 5′ of the dielectric 5, although it has at two opposing ends flattenings 7″ formed, as it were, as a result of the omission of an isosceles-rectangular triangle. Generally, the outline 7′ may therefore also be an n-polygonal outline or contour or even be provided with a curved outer delimitation 7′.
The aforementioned earth surface 3, although also the radiation surface 7, is sometimes referred to as a “two-dimensional” surface, as its thickness is so low that it is scarcely possible to describe it as a “volume body”. The thickness of the earth surface and the radiation surface 3, 7 is conventionally less than 1 mm, i.e. generally less than 0.5 mm, in particular less than 0.25 mm, 0.20 mm, 0.10 mm.
The patch antenna A described hereinbefore can, for example, consist of a conventional commercial patch antenna, preferably of what is known as a ceramic patch antenna in which, that is to say, the dielectric carrier layer 5 is made of a ceramic material. As will become apparent from the remainder of the description, there may also be configured, beyond the patch antenna A described hereinbefore, a patch antenna in the sense of a stacked patch antenna in which there is additionally provided, with lateral of vertical offset from the upper radiation surface 7, a patch assembly 13 comprising a first primary patch element 53 and a second secondary patch additional element 55. In this case, the first parasitic patch element 53 is configured in such a way that it has, compared to the aforementioned earth surface 3 and the radiation surface 7, a three-dimensional structure with a differing, i.e. greater, height or thickness.
Preferably, use is made of a support means 19 having a thickness or height 17, in particular a dielectric support means 19, via which the primary patch element 53 is held and supported. This dielectric support means 19 consists preferably of an adhesion or mounting layer 19′ (
The stacked patch antenna as described is positioned on a chassis B which in
The primary patch element 53 can, for example, consist of an electrically conductive, upwardly open, box-shaped metal body having appropriate longitudinal and transverse extensions and sufficient height.
As may be seen from the three-dimensional view according to
In the exemplary embodiment shown, the patch element 53 has a longitudinal extension and a transverse extension which, on the one hand, are greater than the longitudinal and transverse extensions of the radiation surface 7 and/or, on the other hand, are also greater than the longitudinal and transverse extensions of the dielectric carrier 5 and/or of the earth surface 3 located therebelow.
As may be seen from the figures, the parasitic patch assembly 13 is divided into two and comprises the primary patch element 53 which rests on the carrier means 19 or is fastened and held thereon and is configured in the manner of an upwardly open box and comprises a base surface or central surface 153 which, in the exemplary embodiment shown, is provided with a peripheral edge or a peripheral web 53b (that is to say, generally a corresponding elevation 53b) which rises transversely, in particular perpendicularly, from the plane of the base surface 153 which is also parallel to the earth surface. A patch element 53 of this type can, for example, be produced by cutting and tilting from an electrically conductive metal sheet, wherein the peripheral webs 53b can be electrically connected to one another in the corner regions, for example by soldering (wherein recesses may furthermore also be provided in the central region 153, as will be examined in greater detail hereinafter).
The secondary patch additional element 55, which in the exemplary embodiment shown is likewise box-shaped, in the manner of a volume body having a corresponding length and width and height, is then located above this primary patch element 53. The configuration of the length and width is such that the dimensions are, for example, at least slightly smaller than the free inner length and transverse length between the peripheral webs 53b of the primary patch element 53. That is to say, this allows the secondary patch element, i.e. the secondary patch additional element 55, to dip to differing degrees into the interior 53a of the lower patch element 53. In other words, the lowest level, i.e. the bottom delimiting plane 55′ comes to lie in the interior 53a of the primary patch element 53, i.e. below the upper delimiting plane 53′ which is defined by the upper peripheral rim of the webs or edges or outer walls 53b.
However, as an alternative to a volume body formed in this way, the secondary patch additional element 55 can also be configured in such a way that it is formed, like the lower patch element 53, in the manner of an open box with an interior 55a (see
The patch additional element 55 thus described is now held by a separate support means 61, preferably in the form of a hood or housing 61′ covering and receiving the antenna.
This embodiment allows tolerance errors easily to be compensated for as a result of the fact that this patch additional element 55 can dip into the lower primary patch element 53 to differing degrees depending on the resulting overall construction of the patch antenna, including the primary patch element 53 and the patch additional element 55, and also depending on the height of the hood 61 and the available internal dimension below this hood 61. This allows tolerance errors to be compensated for.
The variation according to
It may therefore be seen from the illustrated construction that it is entirely possible for the overall height 114 of the patch assembly 13 to vary in accordance with the differing tolerance conditions. This is achieved as a result of the fact that the patch assembly 13 is divided at least into two and comprises the two components which may if appropriate be positioned at differing relative distance from one another namely the patch element 53 and the patch additional element 55.
The thickness of the patch assembly 13 as a whole should preferably have a dimension which is not just twice, 3, 4 or 5 times, etc. but rather above all 10 times, 20, 30, 40, 50, 60, 70, 80, 90 and/or 100 and more times the thickness of the earth surface 3 and/or the thickness of the radiation surface 7.
In the exemplary embodiment shown, the thickness or height 114 of the patch assembly 13 as a whole is equal to or greater than a distance 17 between the underside of the patch element 53 and the upper side of the radiation surface 7. On the other hand, this distance should also be not less than 0.5 mm, preferably greater than 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or equal to or greater than 1 mm. Values of about 1.5 mm, i.e. generally between 1 mm and 2 mm or 1 mm and 3 mm, 4 mm or up to 5 mm are entirely sufficient.
Furthermore, it may also be seen that the height or thickness 114 of the three-dimensional patch assembly 13 is preferably less than the height or thickness 15 of the dielectric carrier 5. Preferably, the overall thickness or overall height 114 of the patch assembly 13 has a dimension corresponding to less than 90%, in particular less than 80%, 70%, 60%, 50% or even less than 40% and if appropriate 30% or less than 20% of the height or thickness 15 of the carrier element 5.
In addition, no limitation need necessarily be placed on the above-mentioned height. Therefore, the height or thickness 114 of the three-dimensional patch assembly 13 can also have a greater, and above all much greater, height or thickness than the thickness or height 15 of the dielectric carrier 5. In other words, this height or thickness 15 of the carrier element 5 may, for example, also have a dimension corresponding to up to 1.5 times, 2 times, 4, 5, 6, 7, 8, 9 and/or 10 and more times the height or thickness 15 of the carrier element 5.
On the other hand, the thickness or height 114 of the patch assembly 13 as a whole should preferably be greater than the distance dimension 17 between the radiation surface 7 and the underside 13b of the patch element 13.
The height 114a of the lower patch element 53 and the height 114b of the upper patch additional element 55 are preferably the same so as to allow maximum tolerance compensation. Preferably, at least the two individual heights 114a and 114b (
Obviously, the upper patch additional element 55 is also electrically conductive or provided on its outside or if appropriate with a cavity body having a conductive inside. Therefore, this body may likewise consist of metal or of a plastics material or a dielectric body which is coated if appropriate with an electrically conductive layer. In practice, use may in this case be made of an installation within a hood in which the upper second patch element 55 optionally comes to lie with its lower delimiting plane 55 only at the level of the upper delimiting plane 53′ of the lower patch element 53, or even is positioned slightly thereabove.
Merely for the sake of completeness, it should also be noted that the overall construction of the lower and upper patch elements may also be inverted in such a way that, for example, the upper patch element 55, the outer contours of which are smaller, is constructed on the carrier means 19 and the patch element 53, which is shown at the bottom in the figures, is fastened and/or held to a hood; that is to say, in other words, the patch element which is then on top overlaps the lower patch element, and the lower patch element can dip in the upper patch element. However, this would lead to an increase in the size of the dimensions of the hood, and this is in principle less desirable.
In principle, it should also be noted that one respective part of the patch assembly 13 as a whole, which part is smaller and can dip into the other respective patch element or patch additional element (which is configured in the manner of an open box), may be configured as a volume body (i.e. a solid body) or likewise as a box which is open toward one side. In this case, the open side of the box-shaped patch element 53 or patch additional element 55 thus configured lies preferably in each case on the side facing the other patch element. In other words, the open sides of the patch element 53 and of the patch additional element 55 therefore lie on the two mutually facing sides. In principle, the opening side may, in particular in the case of the smaller patch additional element 55, also be configured on the side which is remote from the patch element 53.
In conclusion, it will be noted merely in principle with reference to
In the exemplary embodiment according to
Described hereinbefore are exemplary embodiments in which, as has been shown in the drawings, the patch element 53 and the patch additional element 55 dip at least partly one inside the other. As mentioned hereinbefore, the two patch elements 53, 55 can also be arranged in such a way that the lower delimiting plane of the upper patch element and the upper delimiting plane of the lower patch element lie precisely in one plane or even in such a way that a distance is formed between these two delimiting planes. The arrangement should in this case be such that the maximum distance between the upper delimiting plane 53′ of the primary patch element 53 and the lower delimiting plane 55′ of the patch additional element 55 is less than 5 times the height 114b of the patch additional element 55, preferably is less than 4 times, 3 times, 2 times and in particular 1 times the height 114b of the patch additional element 55 or even is less than half the height 114b.
Finally, it should also be noted, with regard to the exemplary embodiment according to
